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

*A. Yu Mollaev, I. K. Kamilov, R. K. Arslanov, U.Z. Zalibekov

Pressure control of magnetic clusters in strongly inhomogeneous ferromagnetic chalcopyrites

• T. R. Arslanov and co-workers*

e-mail: arslanovt@gmail.com Amirkhanov Institute of Physics, DSC RAS 367003 Makhachkala, Russia

Collaboration

• L. Kilanski, R. Minikaev, A. Reszka, S. Lόpez-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-V2

ZnGeP2 ZnSnAs2 ZnGeAs2

TC=350 K

CdGeAs2 CdGeP2

TC=355 K

Mn - Doped

TC=367 K

TC=335 K

Is it really intrinsic ferromagnetism? NO!

Problematic?

• 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

7000% at 30K to 200% at 300K

• 1. Seldom been studied and have usually not been well controlled
• 2. Need best self-organization of the clusters
• 3. No direct evidence for spin carrier polarization by clusters

GOOD! (1-2) NECESSARY A NEW APPROACH?

Pressure effect in CdGeAs2:Mn

Two pressure-induced transitions in CdGeP2:Mn

1.4 1.6 1.8 2.0 2.2 0.10 0.12 0.14 0.16 0.18 0.20 0.22

Pressure (GPa) Mn doping

1.040 1.240 1.440 1.640 1.820

ac susceptibility

1st FM-NM transition 2nd FM-NM transition

10

10

Ge0.99P0.01 Cd0.99P0.01 Cd0.46Ge0.32P0.22

Ge K P K P L Ge K Ge L Cd L

Intensity [counts]

Cd L Ge K Ge K P K P L Ge L Mn K

2 4 6 8 10 12 10

10

Cd0.26Mn0.01Ge0.28P0.45 Mn0.53P0.47

E [keV]

10 m 1 2 3 4 5 25 m

Two pressure-induced transitions in CdGeP2: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?

A schematic illustration of strongly inhomogeneous Cd1-xMnxGeP2 with MnP 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.

1 2 3 4 5 10

• 1

10 10

 RH / RHo Pressure (GPa)

CdGeP2

(a)

1 2 3 4 5 10

• 3

10

• 2

10

• 1

10 10

decrease RHRH

Pressure (GPa)

• 
• RH/RH0

increase

(b)

CdGeP2→CdP2+Ge

• A. Yu. Mollaev, et al, High Press.
• Res. 26, 387 (2006).

CdGeP2 →CdP+GeP CdGeP2→Cd+GeP2

• S. Lόpez-Moreno, report (2013).

x0.135 – optimal Mn doping

DFT calculations for MnP clusters in CdGeP2:Mn

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. 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).

Thank you for attention!