Effect of Misfit Strain in (Ga,Mn)(Bi,As) Epitaxial Layers on Their Magnetic and Magneto-Transport Properties

Abstract

Effect of misfit strain in the layers of (Ga,Mn)(Bi,As) quaternary diluted magnetic semiconductor, epitaxially grown on either GaAs substrate or (In,Ga)As buffer, on their magnetic and magneto-transport properties has been investigated. High-resolution X-ray diffraction, applied to characterize the structural quality and misfit strain in the layers, proved that the layers were fully strained to the GaAs substrate or (In,Ga)As buffer under compressive or tensile strain, respectively. Ferromagnetic Curie temperature and magnetocrystalline anisotropy of the layers have been examined by using magneto-optical Kerr effect magnetometry and low-temperature magneto-transport measurements. Post-growth annealing treatment of the layers has been shown to enhance the hole concentration and Curie temperature in the layers.

Evidence for the homogeneous ferromagnetic phase in (Ga,Mn)(Bi,As) epitaxial layers from muon spin relaxation spectroscopy

“…Composition of the layers has been examined with the use of secondary-ion mass spectrometry (SIMS). The high structural perfection of the layers and good quality of their interfaces were confirmed in our previous high-resolution X-Ray diffraction (HR-XRD) measurements 16 .…”

“…17 , to reduce the concentrations of arsenic antisite and interstitial Mn defects in the layers. As proved by the HR-XRD examination 16 , all the layers were pseudomorphically strained either to the GaAs substrate or to (In,Ga)As buffer under compressive or tensile strain, respectively. After the growth the layers were subjected to a low-temperature annealing treatment performed in air at the temperature of 180 °C during 50 h to improve their structural quality and magnetic properties 15,18 .…”

Novel Quaternary Dilute Magnetic Semiconductor (Ga,Mn)(Bi,As): Magnetic and Magneto-Transport Investigations

“…Their magnetic properties were similar to those of the ternary (Ga,Mn)As layers [14]. The easy axes of magnetization in the layers grown under compressive and tensile misfit strain were in plane and out of plane of the layer, respectively [13]. Their longitudinal magneto-resistance and the planar Hall resistance were significantly enhanced as a result of Bi incorporation [15].…”

“…We used a standard lock-in technique with a photo-elastic modulator operating at 50 kHz and a Si-diode detector. Magnetic hysteresis loops were measured in the temperature range 6−150 K, in magnetic fields up to 2 kOe oriented in the plane of the layers [13]. Magneto-transport measurements were carried out on Hall bars aligned along the [110] crystallographic direction, having 100 μm width and 200 μm distance between the voltage contacts.…”

“…Recently, homogeneous layers with a high structural perfection of the (Ga,Mn)(Bi,As) quaternary dilute magnetic semiconductor, containing up to 6 % Mn and 1 % Bi, have been grown with LT-MBE under compressive misfit strain, on GaAs substrate [11,12], as well as under tensile misfit strain, on (In,Ga)As buffer layer [13]. Their magnetic properties were similar to those of the ternary (Ga,Mn)As layers [14].…”