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Title: (Sr{sub 1-x}Na{sub x})(Cd{sub 1-x}Mn{sub x}){sub 2}As{sub 2}: A new charge and spin doping decoupled diluted magnetic semiconductors with CaAl{sub 2}Si{sub 2}-type structure

Abstract

We report the synthesis and characterization of a new bulk diluted ferromagnetic semiconductor via Na and Mn co-doping in SrCd{sub 2}As{sub 2} with a hexagonal CaAl{sub 2}Si{sub 2}-type structure. Together with carrier doping via (Sr,Na) substitution, spin doping via (Cd,Mn) substitution results in ferromagnetic order with Curie temperature of T{sub C} up to 13 K. Negative magnetoresistance is assigned to weak localization at low temperatures, where the magnetization of samples becomes saturated. The hexagonal structure of (Sr{sub 1−x}Na{sub x})(Cd{sub 1−x}Mn{sub x}){sub 2}As{sub 2} can be acted as a promising candidate for spin manipulations owing to its relatively small coercive field of less than 24 Oe.

Authors:
; ; ; ; ; ; ;  [1];  [2];  [1];  [3]
  1. Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)
  2. School of Materials Science and Engineering, Hefei University of Technology, Hefei, Anhui 230009 (China)
  3. (China)
Publication Date:
OSTI Identifier:
22598873
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 120; Journal Issue: 8; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CARRIERS; CURIE POINT; MAGNETIC SEMICONDUCTORS; MAGNETIZATION; MAGNETORESISTANCE; SPIN; SYNTHESIS; TEMPERATURE RANGE 0065-0273 K

Citation Formats

Chen, Bijuan, Deng, Zheng, Li, Wenmin, Gao, Moran, Zhao, Guoqiang, Yu, Shuang, Wang, Xiancheng, Liu, Qingqing, Li, Zhi, Jin, Changqing, E-mail: Jin@iphy.ac.cn, and Collaborative Innovation Center of Quantum Matter, Beijing 100190. (Sr{sub 1-x}Na{sub x})(Cd{sub 1-x}Mn{sub x}){sub 2}As{sub 2}: A new charge and spin doping decoupled diluted magnetic semiconductors with CaAl{sub 2}Si{sub 2}-type structure. United States: N. p., 2016. Web. doi:10.1063/1.4961565.
Chen, Bijuan, Deng, Zheng, Li, Wenmin, Gao, Moran, Zhao, Guoqiang, Yu, Shuang, Wang, Xiancheng, Liu, Qingqing, Li, Zhi, Jin, Changqing, E-mail: Jin@iphy.ac.cn, & Collaborative Innovation Center of Quantum Matter, Beijing 100190. (Sr{sub 1-x}Na{sub x})(Cd{sub 1-x}Mn{sub x}){sub 2}As{sub 2}: A new charge and spin doping decoupled diluted magnetic semiconductors with CaAl{sub 2}Si{sub 2}-type structure. United States. doi:10.1063/1.4961565.
Chen, Bijuan, Deng, Zheng, Li, Wenmin, Gao, Moran, Zhao, Guoqiang, Yu, Shuang, Wang, Xiancheng, Liu, Qingqing, Li, Zhi, Jin, Changqing, E-mail: Jin@iphy.ac.cn, and Collaborative Innovation Center of Quantum Matter, Beijing 100190. 2016. "(Sr{sub 1-x}Na{sub x})(Cd{sub 1-x}Mn{sub x}){sub 2}As{sub 2}: A new charge and spin doping decoupled diluted magnetic semiconductors with CaAl{sub 2}Si{sub 2}-type structure". United States. doi:10.1063/1.4961565.
@article{osti_22598873,
title = {(Sr{sub 1-x}Na{sub x})(Cd{sub 1-x}Mn{sub x}){sub 2}As{sub 2}: A new charge and spin doping decoupled diluted magnetic semiconductors with CaAl{sub 2}Si{sub 2}-type structure},
author = {Chen, Bijuan and Deng, Zheng and Li, Wenmin and Gao, Moran and Zhao, Guoqiang and Yu, Shuang and Wang, Xiancheng and Liu, Qingqing and Li, Zhi and Jin, Changqing, E-mail: Jin@iphy.ac.cn and Collaborative Innovation Center of Quantum Matter, Beijing 100190},
abstractNote = {We report the synthesis and characterization of a new bulk diluted ferromagnetic semiconductor via Na and Mn co-doping in SrCd{sub 2}As{sub 2} with a hexagonal CaAl{sub 2}Si{sub 2}-type structure. Together with carrier doping via (Sr,Na) substitution, spin doping via (Cd,Mn) substitution results in ferromagnetic order with Curie temperature of T{sub C} up to 13 K. Negative magnetoresistance is assigned to weak localization at low temperatures, where the magnetization of samples becomes saturated. The hexagonal structure of (Sr{sub 1−x}Na{sub x})(Cd{sub 1−x}Mn{sub x}){sub 2}As{sub 2} can be acted as a promising candidate for spin manipulations owing to its relatively small coercive field of less than 24 Oe.},
doi = {10.1063/1.4961565},
journal = {Journal of Applied Physics},
number = 8,
volume = 120,
place = {United States},
year = 2016,
month = 8
}
  • Here, we report the successful synthesis of a spin- and charge-decoupled diluted magnetic semiconductor (DMS) (Ca,Na)(Zn,Mn){sub 2}As{sub 2}, crystallizing into the hexagonal CaAl{sub 2}Si{sub 2} structure. The compound shows a ferromagnetic transition with a Curie temperature up to 33 K with 10% Na doping, which gives rise to carrier density of n{sub p} ∼ 10{sup 20 }cm{sup −3}. The new DMS is a soft magnetic material with H{sub C} < 400 Oe. The anomalous Hall effect is observed below the ferromagnetic ordering temperature. With increasing Mn doping, ferromagnetic order is accompanied by an interaction between the local spin and mobile charge, giving rise to a minimum inmore » resistivity at low temperatures and localizing the conduction electrons. The system provides an ideal platform for studying the interaction of the local spins and conduction electrons.« less
  • Substantial ab initio calculations are carried out in this study to further support the conceptual idea proposed by us recently, which is increasing the percentage of substitutional doping of magnetic ions (Mn) in group-IV-semiconductor-based diluted magnetic semiconductors (DMS) by co-doping with another conventional electronic dopant. Kinetic as well as energetic characteristics of the microscopic co-doped system are explored in detail. The n-p pair formed by an n-type electronic dopant and a p-type substitutional Mn atom is found to be a stable conguration in both Ge and Si. The Mn atoms are also found to be kinetically easier to move frommore » interstitial sites to substitutional sites in the presence of a neighboring n-type electronic dopants. Magnetic coupling between two Mn ions in Ge is found to be oscillatory between positive (ferromagnetic) and negative (antiferromagnetic) values with increasing Mn-Mn distance, whereas in Mn/As co-doped Ge all coupling parameters are positive except for the the nearest-neighbor one, and this qualitative dierence does not change with doping level. On the other hand, in Mn doped Ge, when the magnetic coupling is plotted along dierent directions, the oscillatory behavior is gone, indicating the oscillation is from anisotropy rather than a RKKY-form interaction. For Mn doped Si, all coupling values except for the nearest neighbor one are positive and do not change much upon the co-doping. An unconventional magnetic anisotropy, which is the dependence of magnetic coupling on the relative positions of magnetic ions and their neighboring assistant dopants, is also studied. Then the calculated magnetic coupling is mapped to a classical Heisenberg model and Monte Carlo simulation is employed to get the Curie temperature Tc. Tc of Mn/As co-doped Ge is found to be 264K at 5% Mn doping, whereas no ferromagnetic order is present in Mn doped Ge with the Mn concentration ranging from 3.13% to 6%. The homogeneously doped Ge by Mn is thus a spin glass, and Monte Carlo simulation yield a spin-glass phase transition happens at 5K at 5% doping.« less
  • Electrochemical oxidation of (triazatetrabenzoporphyrinato)nickel(II) or (triazatetrabenzoporphyrinato)copper(II), Ni(tatbp) or Cu(tatbp), dissolved in 1-chloronaphthalene in the presence of the perrhenate ion affords the new molecular conductors (Ni(tatbp)){sub 3}(ReO{sub 4}){sub 2}{center dot}C{sub 10}H{sub 7}Cl and (Cu(tatbp)){sub 3}(ReO{sub 4}){sub 2}{center dot}C{sup 10}H{sub 7}Cl. The isostructural compounds are composed of partially ligand-oxidized (+2/3) M(tatbp) molecules that form trimerized stacks. Trimerization of the conducting stacks renders the compounds semiconductors with conductivity along the needle axis (crystallographic a) in the range of 2.5 {times} 10{sup {minus}4}-3.0 {times} 10{sup {minus}4} {Omega}{sup {minus}1} cm{sup {minus}1} and an activation energy for conduction in the range of 0.24-0.26 eV. Magnetic susceptibilitymore » measurements on the Ni(II) derivative show that the valence band has the diamagnetic ground state expected for a semiconductor. Nonetheless, the valence-band electrons are shown to mediate a strong intratrimer Cu-Cu coupling characterized by a Weiss constant {Theta} = {minus}5.2 K in the Cu(II) analogue. The magnetic properties are rationalized in terms of a band structure derived by considering the trimers as weakly interacting supermolecules, with {Theta} dominated by intratrimer interactions. A structure determination was performed on the Cu(II) analogue.« less