Abstract
We investigated the structural and magnetic properties of Cr1-delta Te thin films grown on CdTe(001) layers by molecular beam epitaxy (MBE) with systematic variations of the ratio between Cr and Te fluxes and the substrate temperature T-s during the growth. Cr1-delta Te of the hexagonal structure (hex-Cr1-delta Te) was always formed irrespective of the growth conditions, but the growth orientation was different depending on the Cr/Te flux ratio and T-s. Hex-Cr1-delta Te was grown in the [0001] axis in the range of small Cr/Te ratios and high T-s while it was also grown in the direction normal to the (1-102) plane at larger Cr/Te ratios or lower T-s. Hex-Cr1-delta Te films grown in the both orientations show ferromagnetism, but they exhibit a clear contrast in the held dependence of perpendicular magnetization at 2 K; a square hysteretic loop in the film grown in the [0001] axis versus a round-shape loop in the film grown in the direction normal to the (1-102) plane. Moreover, the films grown in the [0001] axis at the smallest Cr/Te ratio show variations of ferromagnetic properties with Curie temperature (T-c) and the coercivity (H-c) varying according to the value of T-s. (C) 2015 Elsevier B.V. All rights reserved.