In this study, we investigated the structural, optical, and magnetic properties of GaSbMn thin films fabricated via magnetron sputtering on a glass substrate. To introduce Mn into the GaSb matrix at low concentrations, the substrate temperatures were varied from 200 °C to 400 °C. The X-ray results show that the thin films are polycrystalline with a preferential orientation in the (220) direction of GaSb. accompanied by a secondary phase of MnSb. Raman spectroscopy revealed the presence of vibrational phonon modes of GaSb and a Coupled LO-Phonon-Plasmon Mode (CLOPM). The carrier concentration, derived from ωₚ, ranged from approximately 1018 to 1019 cm−3. The magnetization behavior was studied using temperature cycling (H fixed) and field cycling measurements (T fixed). The magnetization loops at room temperature show that Mn-doped GaSb films exhibit weak magnetic behavior. The Curie temperature, TC, was determined from the magnetization vs. temperature curves. TC takes high values in the range of 300 K to 570 K, which is related to the formation of MnxSby nanoparticles embedded into the GaSb matrix.
Aims: In this work, we studied the influence of Mn content on
GaSb thin films deposited by magnetron R.F. sputtering. To this end, the
structural, morphological, optical, and magnetic properties were analyzed and
correlated with the experimental conditions.
Study Design: Experimental and theoretical study.
Place and Duration of Study: Laboratorio de Nanoestructuras
Semiconductoras, Departamento de Física y Química, Universidad Nacional de
Colombia, sede Manizales, Manizales - Colombia, between January 2021 and
February 2022.
Methodology: GaSbMn thin films were fabricated using a
non-epitaxial growth method, specifically magnetron sputtering, with variations
in growth temperature. To study the morphological, structural, optical, and
magnetic properties and to correlate these with the experimental conditions,
X-ray diffraction, EDS-SEM, Raman spectroscopy, and magnetization measurements
were carried out.
Results: GaSbMn thin films exhibit intriguing paramagnetic
properties that are contingent upon experimental parameters. Through structural
analysis, we identified the formation of MnxSby
nanoparticles embedded within the GaSb matrix. The observed MnSb-like phonon
modes at 242 cm-1 (LVM), 251 cm-1 (TO), and 264 cm-1
(LO) align well with the reported vibrational modes of MnSb documented in the
literature. Estimating a hole density of approximately 1019 cm-3
from the CLOPM frequency (ωp) in Raman spectroscopy further
supports our findings. The Mn2Sb phase predominantly contributes to
magnetization at elevated temperatures. Utilizing the mean-field model, we can
compute the mean potential resulting from dipolar interactions between any pair
of moments μi and μj at a distance rij.
Conclusion: GaAsMn thin films exhibit notable magnetic
properties that vary with the growth conditions. Long-range interactions among
isolated magnetic moments were analyzed using the mean-field model,
demonstrating that the dipolar interaction field is influenced by the growth
temperature. The high Curie temperatures observed in the samples are attributed
to the presence of the Mn1+xSb phase.
Author (s)
Details
Camilo. A.
Pulzara-Mora
Laboratorio de Nanoestructuras Semiconductoras, Facultad de Ciencias
Exactas y Naturales, Universidad Nacional de Colombia, sede Manizales,
Manizales, Caldas, Colombia.
José Doria-Andrade
Laboratorio de Materialografia, Facultad de Ingeniería, Institución
Universitaria Pascual Bravo, Medellín, Colombia.
Andres Rosales-Rivera
Laboratorio de Magnetismo y Materiales Avanzados, Facultad de Ciencias
Exactas y Naturales, Universidad Nacional de Colombia, Sede Manizales,
Manizales, Caldas, Colombia.
Álvaro Pulzara-Mora
Laboratorio de Nanoestructuras Semiconductoras, Facultad de Ciencias
Exactas y Naturales, Universidad Nacional de Colombia, sede Manizales,
Manizales, Caldas, Colombia.
Please see the book here:- https://doi.org/10.9734/bpi/strufp/v6/1058
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