HFI/NQI 2007 (eBook)

Title Page 
3 
Copyright Page 
4 
Table of contents 
5 
Foreword 16
Conference Photo Participants 20
EFG calculations for Cu2+ compounds 23
Abstract 23
Keywords 23
1 Introduction 23
2 Data 24
3 Calculation method 24
4 Results 25
5 EFG analysis 25
6 Other properties 26
7 Conclusions 27
References 27
First principles study of nuclear quadrupole interactions in the molecular solid BF3 and the nature of binding between the molecules 
28 
Abstract 28
Keywords 28
1 Introduction 29
2 Procedure 29
3 Results and discussion 30
4 Conclusion 32
References 32
Hyperfine interactions of half-metallic diluted antiferromagnetic semiconductors 
34 
Abstract 34
Keywords 34
1 Introduction 34
2 Theoretical framework 35
3 Results and discussions 36
4 Summary 38
References 38
Electronic properties of HfXY intermetallic compounds (X =Si, Ge Y =S, Se, Te)
39 
Abstract 39
Keywords 39
1 Introduction 39
2 Results and discussion 41
3 Summary 42
References 43
Electronic properties of Hf2X intermetallic compounds(X =AI, Si, Ni, Ga and Ge) 
44 
Abstract 44
Keywords 44
1 Introduction 44
2 Results and discussion 45
3 Summary 48
References 48
Theory of electronic structure and nuclear quadrupole interactions in the BF3-NH3complex and methyl derivatives 
49 
Abstract 49
Keywords 50
1 Introduction 50
2 Procedure 50
3 Results and discussion 51
4 Conclusion 53
References 53
Nuclear quadrupole interactions and electronic structure of BF3 . H20 complex 
55 
Abstract 55
Keywords 55
1 Introduction 55
2 Procednre 56
3 Results and discussion 58
4 Conclusion 60
References 60
Understanding of nuclear quadrupole interactions of 35CI, 79Br and 129I and binding energies of solid halogens at first-principles level 
61 
Abstract 61
Keywords 62
1 Introduction 62
2 Procedure 62
3 Results and discussion 64
4 Conclusion 66
References 66
Nuclear spin manipulation in interfaces of diluted magnetic semiconductors 
68 
Abstract 68
Keywords 68
1 Introduction 68
2 Calculation 69
3 Results and discussions 69
References 72
Magnetic properties of Heisenberg triangular antiferromagnet VIS cluster studied by NMR 
73 
Abstract 73
Keywords 73
1 Introduction 73
2 Experimental 74
3 Results and discussion 74
References 76
Temperature dependence of the magnetic hyperfine field at cerium impurity in Co 
77 
Abstract 77
Keywords 77
1 Introduction 77
2 Experimental procedure 78
3 Results and discussion 78
References 81
Magnetic hyperfine fields at Gd and in sites in GdPdIn compound 
82 
Abstract 82
Keywords 82
1 Introduction 82
2 Experimental 83
3 Results and discussion 83
References 86
Study of hyperfine interactions in the intermetallic compound CePd2Si2 using PAC technique with 111Cd as probe nuclei 
87 
Abstract 87
Keywords 87
1 Introduction 87
2 Experiment 88
3 Results and discussions 88
References 90
Mössbauer characterization of Fe-doped ZnO prepared by mechanical milling 
92 
Abstract 92
Keywords 92
1 Introduction 92
2 Experimental 93
3 Results and discussion 93
3.1 XRD measurements 93
3.2 SEM images 94
3.3 Mossbauer spectroscopy 95
4 Conclusions 97
References 97
Temperature dependence of the hyperfine fields in NiFe2O4 and CuFe2O4 oxides 
98 
Abstract 98
Keywords 98
References 103
Hyperfine interactions at R and In sites in RNiIn (R =Gd, Tb, Dy, Ho) compounds measured by perturbed angular correlation spectroscopy 
105 
Abstract 105
Keywords 105
1 Introduction 106
2 Experimental procedure 106
3 Results and discussion 107
References 109
Synthesis and thermal transformations of zinc-substituted magnetites 
111 
Abstract 111
Keywords 111
1 Introduction 111
2 Experimental details 112
3 Results and discussion 113
4 Conclusions 115
References 115
Magnetic characterization of maghemite nanoparticles dispersed in surface-treated polymeric template 
116 
Abstract 116
Keywords 116
1 Introduction 116
2 Experimental 117
3 Results and discussion 117
References 120
Investigation of the different nature of magnetic hyperfine fields of Ce probes in Gd and Co matrices 
121 
Abstract 121
Keywords 121
1 Introduction 121
2 Experimental resnIts 122
3 Details of the calculations 122
4 Discussion 123
References 125
Magnetic properties of rare-earth permanent magnets under a high radiation environment 
126 
Abstract 126
Keywords 126
1 Introduction 126
2 Experiments 127
2.1 Demagnetization 127
2.2 TDPAC measurement 127
3 Discussion 129
References 129
Defects in semiconductors-resultsfrom Mössbauer spectroscopy 
130 
Abstract 130
Keywords 130
1 Introduction 130
2 Elementary point defects in 111-V semiconductors 131
3 The fate of ion-implanted s7Mn.S7Fe in silicon, Sit - xGex alloys and other group IV elements and compounds 133
3.1 Fe in silicon and group IV elements 133
3.2 The diffusivity of interstitial Fei in silicon and SiGe alloys 
136 
3.3 Interactions of recoil-created interstitial Fei 
137 
3.4 Fe in diamond and SiC 140
References 142
Site preferences of indium impurity atoms in intermetallics having AI3Ti or AI3Zr crystal structures 
143 
Abstract 143
Keywords 143
References 147
Phosphorus-doped silicon under uniaxial tensile strain investigated by PAC 
148 
Abstract 148
Keywords 148
1 Introduction 148
2 Experimental details 149
3 Results and discussion 149
4 Conclusions 151
References 152
The gap level of bond-centred muonium in diamond 153
Abstract 153
Keywords 154
1 Introduction 154
2 Experimental 154
3 Results 155
4 Discussion 156
5 Conclusion 157
References 157
Characterization of palladium-related defects in silicon 158
Abstract 158
Keywords 158
1 Introduction 158
2 Experimental details 159
3 Results and discussions 159
4 Conclusions 162
References 162
Low temperature nuclear orientation observations of severe neutron activation damage in e60Tb)TbNiAI4 
163 
Abstract 163
Keywords 163
1 Introduction 163
2 Experimental details 164
3 Results 165
4 Discussion 166
References 167
Simulation of PAC spectra for spin 5/2 probes diffusing via a simple vacancy mechanism in CU3Au-structured intermetallic compounds 
168 
Abstract 168
Keywords 168
References 171
Perturbed angular correlation measurement of the electric field gradient at 181Ta in ZrSi04 and HfSi04 
173 
Abstract 173
Keywords 173
1 Introduction 173
2 Experimental procedure 174
3 Results and discussion 175
4 Conclusions 177
References 178
XRD, TDPAC and LAPW study of HflOB2 under high pressure 
179 
Abstract 179
Keywords 179
1 Introduction 179
2 Experimental details 180
3 Results 181
4 TDPAC data analysis 182
5 Calculations and discussion 183
6 Summary 185
References 185
Determination of quadrupole splitting for 57Fein Ml and M2 sites of both olivine and pyroxene in ordinary chondrites using Mossbauer spectroscopy with high velocity resolution 
187 
Abstract 187
Keywords 187
1 Introduction 187
2 Methods 188
3 Results and discussions 188
4 Conclusion 192
References 193
Study of hyperfine interactions in carbonaceous chondrite Isheyevo (CH/CB) using Mossbauer spectroscopy with high velocity resolution 
194 
Abstract 194
Keywords 194
1 Introduction 194
2 Methods 195
3 Results and discussions 195
4 Conclusion 199
References 199
Study of metal grains extracted from chondrite Tsarev L5 using Mossbauer spectroscopy with high velocity resolution 
201 
Abstract 201
Keywords 201
1 Introduction 201
2 Methods 202
3 Results and discussions 203
4 Conclusion 206
References 206
Temperature dependence of the electric field gradient in GaN measured with the PAC-probe 181Hf 
208 
Abstract 208
Keywords 208
1 Introduction 209
2 Experimental details 209
3 Results and discussion 210
4 Conclusions 214
References 214
Time-differential perturbed angular correlation study of the electric field gradient in Ti2Rh MoSirtype compound 
215 
Abstract 215
Keywords 215
1 Introduction 215
2 Experimental 216
3 Results and discussion 217
References 219
Formation of DX-centers in indium doped CdTe 221
Abstract 221
Keywords 221
1 Introduction 221
2 Experimental details 223
3 Results and discussion 223
4 Summary 227
References 227
Solution of 111ln impurities in the Hf(ZrhAI2 minority phases of Hf(Zr)4AI3 samples 
229 
Abstract 229
Keywords 229
1 Introduction 229
2 Experimental 230
3 Results and conclusion 231
References 235
Characterization of ZnO and ZnO.9SCoO.OsO prepared by sol-gel method using PAC spectroscopy 
236 
Abstract 236
Keywords 236
1 Introduction 236
2 Experimental procedure 237
3 Results and discussion 237
References 240
Temperature dependence of electric field gradient in TbCo03 
241 
Abstract 241
Keywords 241
1 Introduction 241
2 Experimental procedure 242
3 Results and discussion 243
References 245
Evolution under thermal annealing of Mn-doped iron disilicides obtained by ball milling 
246 
Abstract 246
Keywords 246
1 Introduction 246
2 Experimental 247
3 Results and discussion 248
4 Conclusions 250
References 250
The temperature dependence of the EFG for 172Lue72Yb) in GaN 
251 
Abstract 251
Keywords 251
1 Introduction 251
2 Results 252
3 Discussion 253
4 Summary 254
References 254
First PAC experiments in MAX-phases 255
Abstract 255
Keywords 255
1 Introduction 255
2 Experimental details 257
3 Results 258
3.1 Indium loss 258
3.2 The MAX-phase ThInC 258
3.3 The MAX-phase ZrzInC 258
3.4 Compressive stress on ThInC 260
4 Discussion 261
References 262
High temperature perturbed angular correlation studies of Ln2Ni04+c5 Ln=La,Pr,Nd 
263 
Abstract 263
Keywords 263
1 Introduction 263
2 Experiments 264
3 Results 264
4 Discussion 265
5 Conclusions 266
References 267
TDPAC study of Cd-doped SuO 268
Abstract 268
Keywords 269
1 Introduction 269
2 Sample preparation and measurements 270
3 Results and discussion 270
4 Conclusions 273
References 274
Investigation of hyperfine interactions in RM03 (R =La, Nd M =Cr, Fe) antiferromagnetic perovskite oxides using PAC spectroscopy
275 
Abstract 275
Keywords 275
1 Introduction 275
2 Experimental procedure 276
3 Results and discussion 276
References 279
First-principles study of location of Er3+ ion-relationship to understanding of hyperfine interactions in the optoelectronic erbium-silicon system 
280 
Abstract 280
Keywords 280
1 Introduction 281
2 Procedure 281
3 Results and discussion 282
4 Conclusion 284
References 284
Stochastic models of hyperfine interactions in nonequilibrium: an examination of the XYZ model with a trapping-detrapping mechanism 
286 
Abstract 286
Keywords 286
1 Slow trapping-detrapping results (rt/.q> Q <
288 
2 Intermediate trapping-detrapping results 288
3 Rapid trapping-detrapping results (rt/.q> Q <
289 
References 290
Electric field gradient at uN implanted into ZnO 291
Abstract 291
Keywords 291
1 Introduction 291
2 Experimental 292
3 Results and discussion 292
References 295
Electronic structure of substitutional nitrogen impurity in Ti02 studied by the ß-NMR method 
296 
Abstract 296
Keywords 296
1 Introduction 297
2 Experimental 297
3 Results and discussion 298
References 299
Temperature dependence of Knight shifts for 12B in Pt 300
Abstract 300
Keywords 300
1 Introduction 300
2 Experimental 301
3 Results and discussion 301
References 304
Temperature dependence of the lattice locations of boron implanted in germanium 
305 
Abstract 305
Keywords 305
1 Introduction 305
2 Experiment 306
3 Results and discussions 306
References 308
Spin-lattice relaxation of 25AI and 28p in Pt 309
Abstract 309
Keywords 310
1 Introduction 310
2 Experimental 310
3 Results and discussion 310
References 312
Diffusion of 111Cd probes in Ga7Pt3 studied via nuclear quadrupole relaxation 
313 
Abstract 313
Keywords 313
References 316
High-temperature protonic motion and low-temperature lattice deformation in one-dimensional hydrogen-bonded molecular chain in tetramethylpyrazine-chloranilic acid (1:1) 
317 
Abstract 317
Keywords 317
1 Introduction 317
2 Experimental 318
2.1 Sample preparation and identification 318
2.2 35CINQR 318
2.3 'HNMR 318
3 Results and discussion 319
4 Conclusion 322
References 323
DrNQR relaxation of the mixed-valence compound (NH4)4SbmSbvDr12 
324 
Abstract 324
Keywords 324
1 Introduction 324
2 Experimental 326
3 Results and discussion 326
4 Conclusion 329
References 330
Mössbauer study of 57Fe in CVD diamond following 57Mn implantation 
331 
Abstract 331
Keywords 332
1 Introduction 332
2 Experimental details 332
3 Results and discussion 333
4 Conclusions 336
References 336
Theoretical modeling of bifunctional multilayer systems 337
Abstract 337
Keywords 337
1 Introduction 338
2 Background 338
2.1 General 338
2.2 Model systems 339
2.3 Design goals 340
3 Theoretical methodology 340
4 Results 341
5 Summary 345
References 345
Hyperfine interactions in (CuFe2O4)1-x(SnO2)x (x =0, 1, 5, 10 and 20 wt,%) nanocomposites studied by Mössbauer spectroscopy 
347 
Abstract 347
Keywords 347
1 Introduction 347
2 Materials and methods 348
3 Results and discussions 349
4 Conclusion 352
References 352
Study of the evolution of the hyperfine parameters in nanostructured Fe-Mn-Cu system 
353 
Abstract 353
Keywords 353
1 Introduction 353
2 Experimental 354
3 Results and discussion 354
4 Conclusions 356
References 357
Mössbauer study of Sn(Fe)02 prepared by mechanosynthesis 
358 
Abstract 358
Keywords 358
1 Introduction 358
2 Experimental 359
3 Results and discussion 359
4 Conclusion 362
References 362
Synthesis, thermal treatment and characterization of cobalt ferrite-based nanocomposites 
364 
Abstract 364
Keywords 364
1 Introduction 364
2 Experimental 365
3 Data analysis 365
4 Conclusions 369
References 369
Local magnetic fields in the Mo layer of MolFe multilayer 
370 
Abstract 370
Keywords 370
1 Introduction 371
2 Experimental procedures 371
3 Results and discussion 371
References 373
The role of Fe during hydride formation in the Mg-Fe system: a Mossbauer investigation 
374 
Abstract 374
Keywords 374
1 Introduction 374
2 Experimental 375
3 Results 375
4 Discussion 378
References 378
Perturbed angular correlation study of a nanostructured Hf02 film 
379 
Abstract 379
Keywords 379
1 Introduction 379
2 Experimental procedure 380
3 Results and discussion 381
4 Conclusions 383
References 384
Dopants incorporation in ZnO mechanical milled powders sensed by positrons 
385 
Abstract 385
Keywords 385
1 Introduction 385
2 Experimental 386
3 Results and discussion 386
4 Conclusions 390
References 391
Mössbauer effect phase determination in iron oxide-polyaniline nanocomposites 
392 
Abstract 392
Keywords 392
1 Introduction 392
2 Experimental details 393
3 Results and discussion 394
4 Conclusions 397
References 397
Nanostructures in calcia stabilized hafnia thin films observed by PAC as a function of temperature 
398 
Abstract 398
Keywords 398
1 Introduction 399
2 Experimental 399
3 Results and discussion 399
4 Conclusions 403
References 403
NMR study of the isotopically engineered Ge single crystals 
405 
Abstract 405
Keywords 405
References 409
Zero-field splittings ofNQR spectra for bismuth(III) oxy compounds revealed by quadrupole spin echo envelopes 
410 
Abstract 410
Keywords 410
1 Introduction 410
2 Experimental 411
3 Modeling 411
4 Results 411
5 Discussion 412
6 Conclusions 413
References 413
Nuclear spin echo model based on Floquet-Lyapuoov theory 
414 
Abstract 414
Keywords 414
1 Introduction 414
2 Nuclear spin echo model 415
3 Application of the FIoquet-Lyapunov theorem 417
4 Conclusion 420
References 420
35CI NQR and XRD Studies on CS2[Ag(I)xAu(I)1-xCl2l[Au(III)CI4] 
422 
Abstract 422
Keywords 422
1 Introduction 422
2 Experiment 423
3 Results and discussion 423
References 425
Novel pulsed electron spin resonance system and studies of phosphorus in natural silicon 
427 
Abstract 427
Keywords 427
1 Introduction 427
2 Pulsed ESR system 428
3 Experimental results and discussion 428
References 430
Stimulated polarization wave process in spin 3/2 chains 431
Abstract 431
Keywords 431
1 Introduction 431
2 Hamiltonian of the system 432
3 Effective Hamiltonian 433
4 Numerical simulation 435
5 Discussion 436
References 437
Magnetic moment of proton halo nucleus 28p 438
Abstract 438
Keywords 439
1 Introduction 439
2 Experimental 440
3 Results and discussion 441
4 Summary 443
References 443
Production of spin-polarized 17N beam using inverse-kinematics low-energy transfer reactions 
444 
Abstract 444
Keywords 444
1 Introduction 444
2 Experimental procedure 445
3 Result and discussion 447
4 Conclusion 448
References 448
g-Factors of magnetic-rotational states in 85Zr 
449 
Abstract 449
Keywords 449
1 Introduction 449
2 Experimental 450
3 Results and discussion 452
4 Summary 453
References 454
Hyperfine anomalies of Sc isotopes (A = 44, 44 m, 46 and 47) in iron 
455 
Abstract 455
Keywords 455
1 Introduction 455
1.1 Experimental details 456
2 Results 456
2.1 47Sc 456
2.2 44,44mSc and 46Sc 
457 
3 Discussion 459
References 460
Electric quadrupole moments of neutron-rich nuclei 32Al and 31Al 
461 
Abstract 461
Keywords 461
1 Introduction 462
2 Experiment and result 462
3 Discussion 464
References 464
Hyperfine interaction of 25AI in a-Al203 and its quadrupole moment 
465 
Abstract 465
Keywords 466
1 Introduction 466
2 Experimental 466
3 Results and discussion 466
References 469
Magnetic moment of short lived ß-emitter 24mAI 
470 
Abstract 470
Keywords 470
1 Introduction 471
2 Experimental 471
3 Results and discussion 471
References 473
ß·Ray angular distribution from purely nuclear spin aligned 20F 
474 
Abstract 474
Keywords 474
1 Introduction 475
2 Experiment 475
3 Result and discussion 477
References 477
Magnetic moment of 48Sc 478
Abstract 478
Keywords 478
1 Introduction 478
2 Experimental details 479
3 Results and discussion 480
References 481
Polarization of 23Ne, 24m,25AI and 28p produced through single nucleon pickup and charge-exchange reactions at 100 AMeV 
483 
Abstract 483
Keywords 483
1 Introduction 484
2 Experimental 485
3 Results and discussion 485
References 487
Using Mössbauer spectroscopy as key technique in the investigation of nanosized magnetic particles for drug delivery 
488 
Abstract 488
Keywords 488
1 Introduction 488
2 The material platformprovided by magnetic fluids 489
3 Characterization of nanosized magnetic particles in complex systems 491
4 Conclusion 497
References 497
35CI NQR spectra of group 1 and silver dichloromethanesulfonates 
500 
Abstract 500
Keywords 500
1 Introduction 500
2 Experimental 502
3 Results and discussion 503
References 506
New image contrast method in magnetic resonance imaging via ultrasound 
507 
Abstract 507
Keywords 507
1 Introduction 507
2 Theory 508
3 Results 509
4 Discussion 510
References 512
Quadrupole coupling constants and isomeric Mössbauer shifts for halogen-containing gold, platinum, niobium, tantalum and antimony compounds 
513 
Abstract 513
Keywords 513
1 Introduction 514
2 Computational details 515
3 Results and discussion 515
References 521
The DFT-DVM theoretical study of the differences of quadrupole splitting and the iron electronic structure for the rough heme models for a- and ß-subunits in deoxyhemoglobin and for deoxymyoglobin 
523 
Abstract 523
Keywords 523
1 Introduction 523
2 Methods 525
3 Results and discussions 525
4 Conclusion 528
References 529
A study of human liver ferritin and chicken liver and spleen using Mossbauer spectroscopy with high velocity resolution 
530 
Abstract 530
Keywords 530
1 Introduction 530
2 Methods 531
3 Results and discussion 532
4 Conclusion 536
References 536
Ab initio study of the EFG at the N sites in imidazole 
538 
Abstract 538
Keywords 538
1 Introduction 538
2 Theoretical approach 540
3 Results and discussion 540
4 Conclusions 542
References 542
Anomalous HID isotope effect on 35CI NQR frequencies in piperidinium p-chlorobenzoate 
544 
Abstract 544
Keywords 544
1 Introduction 544
2 Experimental 545
3 Results and discussion 547
4 Conclusions 551
References 552
Measurement of electric field gradient at 117 In on the Cu-site in mavicyanin by perturbed angular correlation of . -rays 
554 
Abstract 554
Keywords 554
1 Introduction 554
2 Experiments 555
3 Results and discussion 556
References 557
Investigation of the hyperfine properties of deoxy hemoglobin based on its electronic structure obtained by Hartree-Foek-Roethaan procedure 
559 
1 Introduction 560
2 Procedure 560
3 Results and discussion 562
4 Conclusion 563
References 564
Theoretical investigation of nuclear quadrupole interactions in DNA at first-principles level 
565 
1 Introduction 566
2 Procedure 566
3 Results and discussion 567
4 Conclusions 569
References 570
35CI NQR in glassy crystal, 3-chlorothiophene 571
1 Introduction 571
2 Experimental 572
3 Results and discussion 572
References 575
Study of 14N NQR response to SORe pulse sequence 576
1 Introduction 576
2 Experimental 577
3 Results and discussion 577
4 Conclusion 581
References 581
PAC research in biology 582
1 Introduction 582
2 Reported PAC applications to biological systems 583
3 PAC probes: merits and drawbacks 586
4 Biological applications using 11lIn and 181Hf 586
5 Planned PAC experiments 587
References 588
Laser pumping of ions in a cooler buncher 590
1 Introduction 590
2 Laser spectroscopy of the zirconium region 591
References 593
Optical-coupling nuclear spin maser under highly stabilized low static field 
594 
1 Introduction 594
2 Optical-coupling nuclear spin maser 595
3 Experiment and status of R& D
4 Summary and future 597
References 597
Cross-relaxation in multiple pulse NQR spin-locking 598
1 Introduction 598
2 Experiments 599
3 Theory 600
3.1 Hamiltonian of the system 600
3.2 Effective Hamiltonian 603
3.3 Kinetic equations 604
4 Results and discussions 605
References 608
Fitting PAC spectra with a hybrid algorithm 609
1 Introduction 609
2 The hybrid algorithm 610
3 An application example of the HA 611
4 Discussion and conclusions 612
References 612
Actual concepts of digital PAC-spectroscopy 
613 
1 Introduction 614
2 Concepts of digital signal and data processing in PAC-spectroscopy 614
3 The Braunschweig digital PAC-Spectrometer 616
4 Experimental results 618
5 Conclusions 620
Open Access 620
References 620
Development of atomic-beam resonance method to measure the nuclear moments of unstable nuclei 
622 
1 Introduction 622
2 Experiment 623
3 Prospect 625
References 625
Efficiency-optimized low-cost TDPAC spectrometer using a versatile routing/coincidence unit 
626 
1 Introduction 626
2 Description of the spectrometer 627
3 Equipment performance 632
4 Summary 635
References 636
Hyperfine interactions: the past, the present and the future 
637 
1 The past 637
2 The present 638
3 The future 639
Keyword Index (2007/2008) 640
Author Index (2007/2008) 644

"Hyperfine interactions of half-metallic diluted antiferromagnetic semiconductors (p. 21-22)

Abstract Half-metallic diluted antiferromagnetic semiconductors (HM-AF-DMSs) are magnetic materials that are half-metallic and yet do not exhibit magnetization. The remarkable features of these materials and the possible experimental verifications for determining whether or not a material is a HM-AF-DMS by the detection of hyperfine interactions are discussed on the basis of the first-principles calculations of the electronic structure. Keywords Diluted magnetic semiconductor- Half-metal- Hyperfine field

1 Introduction

Spin-electronics (or spintronics), which is a technology that employs the spin state of electrons and provides a new degree of freedom for storing information, is among the most challenging strategies in the development of electronic devices. One of the key issues in spintronics is half-metallicity, i.e., the property of metallicity in one spin state (say, spin-up) of electrons but insulating in the opposite spin state (spin-down). Although all the half-metals known thus far are ferromagnetic, half-metallicity is not restricted to ferromagnets.

The realization of half-metallic antiferromagnets (more precisely, half-metallic compensated ferrimagnets), which are half-metallic and yet do not exhibit magnetization, might be possible and these materials are expected to be used as a new type of spintronics materials. Since the past few years, several diluted ferromagnetic semiconductors (DMSs) have been theoretically designed (computational materials design). In these DMSs, local magnetic states are formed at the impurity bands that appear in a semiconductor gap. Similarly, half-metallic antiferromagnetic DMSs (HM-AF-DMSs) can be realized for the impurity bands in the gap.

We have proposed such a new type of half-metallic antiferromagnets and named them half-metallic diluted antiferromagnetic semiconductors [2]. In order to realize such systems, we have to introduce at least two different types of magnetic ions into nonmagnetic hosts . In DMSs that contains two types of magnetic ions among which the electron occupation of one type of ion is more than half-filling and that of the other is less than half-filling, the local magnetic moments of the two ions can be coupled anti-parallel to each other. In most cases, such an anti-parallel coupling is more stable than the parallel coupling and also exhibits half-metallicity.

Since half-metallic antiferromagnets do not exhibit magnetization, and moreover since they are disordered and diluted systems, it could be rather difficult to observe their chracterestics. In this study, we propose methods to verify whether or not a material is a half-metallic antiferromagnetic semiconductors. Magnetic circular dicroism (MCD) can be employed as one of the methods for detecting half-metallic antiferromagnetism. Another possible method for the verification of half-metallic antiferromagnetism is the detection of hyperfine interactions.

In order to employ the latter method, we have performed the first-principles calculations of the electronic structure and hyperfine fields of half-metallic antiferromagnetic semiconductors. Although several examples indicate that HM-AF materials might be stable, the fabrications of materials based on group II-VI compounds appear to be relatively easy. As an example of such semiconductors, we consider (Cdl-2xCrxFex)Te and discuss its hyperfine interactions."