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Itinerant Magnetism in Ga‐Rich Ga–Mn–Co Full Heusler Alloys
Author(s) -
Samanta Tamalika,
Srihari Velaga,
Bhobe Preeti A.
Publication year - 2021
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.202000461
Subject(s) - condensed matter physics , curie temperature , materials science , ferromagnetism , magnetism , magnetic moment , magnetization , ground state , electrical resistivity and conductivity , physics , magnetic field , atomic physics , quantum mechanics
Herein, the crystal structure and the magnetic and electrical properties of two Ga‐rich, off‐stoichiometric full Heusler‐type compositionsGa 2 − xMn 1 + x Co with x = 0.2 and 0.4 are investigated. The innate site disorder in the crystal structure is clarified using synchrotron X‐ray diffraction (XRD) studies. Experimentally, it is observed that a control over magnetic ordering temperature ( T C ) and total magnetic moment can be achieved by tuning the Ga:Mn ratio in these alloys. Consequently, for the resultant compositions,Ga 1.8 Mn 1.2 Co andGa 1.6 Mn 1.4 Co , Curie temperatures of ≈245 and 375 K, respectively, are obtained, lying in the vicinity of room temperature. The atomic site disorder arising out of excess Mn leads to spin fluctuation scattering which is reflected in its magnetic and transport properties. Temperature dependence of resistivity shows an anomalous occurrence of a maximum, reflecting a change in the sign of the temperature coefficient of resistance, coincidental withT C . Furthermore, the magnetization results indicate an itinerant‐type ferromagnetic ground state over the Heisenberg‐type state, with the moment values as low as 0.35μ B .