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arXiv · 1802.07056

Electronic phase separation in insulating (Ga,Mn)As with low compensation: Super-paramagnetism and hopping conduction

Ye Yuan·Mao Wang·Chi Xu·René Hübner·Roman Böttger·Rafal Jakiela·Manfred Helm·Maciej Sawicki·Shengqiang Zhou
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Abstract

In the present work, low compensated insulating (Ga,Mn)As with 0.7% Mn is obtained by ion implantation combined with pulsed laser melting. The sample shows variable-range hopping transport behavior with a Coulomb gap in the vicinity of the Fermi energy, and the activation energy is reduced by an external magnetic field. A blocking super-paramagnetism is observed rather than ferromagnetism. Below the blocking temperature, the sample exhibits a colossal negative magnetoresistance. Our studies confirm that the disorder-induced electronic phase separation occurs in (Ga,Mn)As samples with a Mn concentration in the insulator-metal transition regime, and it can account for the observed superparamagnetism and the colossal magnetoresistance.

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Ye Yuan, Mao Wang, Chi Xu, René Hübner, Roman Böttger, Rafal Jakiela, Manfred Helm, Maciej Sawicki, Shengqiang Zhou. 2018-02-20. Electronic phase separation in insulating (Ga,Mn)As with low compensation: Super-paramagnetism and hopping conduction. https://doi.org/10.1088/1361-648x/aaa9a7

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