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Title: Cluster altered magnetic and transport properties in Ge{sub 1−x−y}Mn{sub x}Eu{sub y}Te

Magnetic and transport properties of Ge{sub 1−x−y}Mn{sub x}Eu{sub y}Te crystals with chemical compositions 0.041 ≤ x ≤ 0.092 and 0.010 ≤ y ≤ 0.043 are studied. Ferromagnetic order is observed at 150 < T < 160 K. Aggregation of magnetic ions into clusters is found to be the source of almost constant, composition independent Curie temperatures in our samples. Magnetotransport studies show that below 25 K there is a negative magnetoresistance, which is not linear and has a minimum and above 60 K the magnetoresistance is positive and linear. Negative magnetoresistance detected at T < 25 K is found to be due to a tunneling of spin-polarized electrons between ferromagnetic clusters. A linear positive magnetoresistance is identified to be a geometrical effect related to the presence of ferromagnetic clusters inside the semiconductor matrix. The product of the polarization constant (P) and the inter-grain exchange constant (J), JP, varies between about 0.13 meV and 0.99 meV. A strong anomalous Hall effect is observed for T ≤ T{sub C}, where T{sub C} is the Curie temperature, with coefficients R{sub S} independent of temperature. The scaling analysis of the AHE leads to a conclusion that this effect is due to a skew scattering mechanism.
Authors:
; ; ; ; ; ;  [1] ; ;  [2]
  1. Institute of Physics, Polish Academy of Sciences, al. Lotnikow 32/46, 02-668 Warsaw (Poland)
  2. Institute of Materials Science Problems, Ukrainian Academy of Sciences, 5 Wilde Street, 274001 Chernovtsy (Ukraine)
Publication Date:
OSTI Identifier:
22314343
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 8; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CHEMICAL COMPOSITION; CRYSTALS; CURIE POINT; HALL EFFECT; MAGNETORESISTANCE; POLARIZATION; SCATTERING; SEMICONDUCTOR MATERIALS; SPIN ORIENTATION; TUNNEL EFFECT