T. R. Arslanov and co-workers* e-mail: arslanovt@gmail.com *A. Yu - PowerPoint PPT Presentation

Amirkhanov Institute of Physics, DSC RAS 367003 Makhachkala, Russia Pressure control of magnetic clusters in strongly inhomogeneous ferromagnetic chalcopyrites T. R. Arslanov and co-workers* e-mail: arslanovt@gmail.com *A. Yu Mollaev, I. K. Kamilov, R. K. Arslanov, U.Z. Zalibekov

Collaboration L. Kilanski, R. Minikaev, A. Reszka, S. L ό pez-Moreno, A. H. Romero, M. Ramzan, P. Panigrahi, R. Ahuja, T. Chatterji, V. M. Trukhan, S. F. Marenkin, I.V. Fedorchenko and T. V. Shoukavaya Institute of Physics, Polish Academy of Sciences, Warsaw, Poland Escuela Superior Cd. Sahagun, Universidad Autonoma del Estado de Hidalgo, Hidalgo, Mexico Physics Department, West Virginia University, Morgantown, West Virginia, USA Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden Department of Materials and Engineering, Royal Institute of Technology, Stockholm, Sweden Institute Laue-Langevin, Grenoble, France Scientic-Practical Materials Research Centre (SSPA) of NAS of Belarus, Minsk, Belarus Kurnakov Institute of General and Inorganic Chemistry RAS, Moscow, Russia

II-IV-V 2 ZnGeP 2 Mn - Doped T C =350 K ZnSnAs 2 ZnGeAs 2 T C =367 K T C =355 K CdGeAs 2 T C =335 K CdGeP 2

Is it really intrinsic ferromagnetism? NO!

Problematic? GOOD! 1. Mn distribution is strongly inhomogeneous 2. Curie temperature is higher than 400 K 3. Pronounced anomalous Hall effect up to room temperature 4. A giant positive magnetoresistance is measured from (1-2) 7000% at 30K to 200% at 300K NECESSARY A NEW 1. Seldom been studied and have usually not been well controlled APPROACH? 2. Need best self-organization of the clusters 3. No direct evidence for spin carrier polarization by clusters

Pressure effect in CdGeAs 2 :Mn

Two pressure-induced transitions in CdGeP 2 :Mn 0.22 0.20 1.820 ac susceptibility 1 st FM-NM transition 0.18 Mn doping 1.640 0.16 1.440 0.14 0.12 1.240 2 nd FM-NM transition 0.10 1.040 1.4 1.6 1.8 2.0 2.2 Pressure (GPa) Ge L  Ge 0.99 P 0.01 2 Cd 0.99 P 0.01 Cd L  Cd 0.46 Ge 0.32 P 0.22 4 10 3 P K  Intensity [counts] P L  Ge K  Ge K  1 10  m 3 10 P K  Cd 0.26 Mn 0.01 Ge 0.28 P 0.45 Ge L  Mn 0.53 P 0.47 4 10 Cd L  Mn K  Mn L  P P 4 5 L  L  Ge K  Ge K  3 10 25  m 0 2 4 6 8 10 12 E [keV]

Two pressure-induced transitions in CdGeP 2 :Mn ZF -magnetization for x =0.225 as function of applied pressure. Dashed line corresponds for appearance of second FM state as it further obtained from minor hysteresis loops vs magnetic field measured at pressures up to 2.45 GPa (b) and up to 3.3 GPa (inset).

When chalcopyrite structure is stable under pressure? (b) 1 10 (a) CdGeP 2 →CdP 2 +Ge 1 CdGeP 2 10 increase A. Yu. Mollaev, et al , High Press. 0 10 Res. 26 , 387 (2006).    R H / R Ho    R H  R H  0 10 -1 10 CdGeP 2 → CdP+GeP decrease CdGeP 2 → Cd+GeP 2 -2 10 -     S. L ό pez-Moreno, report (2013). - R H / R H 0 -1 10 -3 10 0 1 2 3 4 5 0 1 2 3 4 5 A schematic illustration of strongly Pressure (GPa) Pressure (GPa) inhomogeneous Cd 1-x Mn x GeP 2 with MnP x  0.135 – optimal Mn doping clusters and substituted Mn atoms in the host When pressure is applied there is a possible separation, which leads to new subproducts due to the pressure-induced decomposition trend.

DFT calculations for MnP clusters in CdGeP 2 :Mn The crystallized micron size cell with Pnma structure were created based on the theoretically crystal optimal parameters. Z. Gercsi and K. G. Sandeman, Phys. Rev. B 81 , 224426 (2010). Several MnP spin congurations were considered: NM FM-I, FM-II and FM-III, varying the value of the total magnetic moment from 1.50  B /f.u., 1.20  B /f.u. and 0.53  B /f.u.

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