Enhanced Magnetic Properties of YCr0.5Mn0.5O3 Thin films fabricated by RF Sputtering.

Abstract

Thin films of rare-earth orthochromites are successfully fabricated using radio frequency sputter technique. The processing parameters like substrate temperature, target-substrate distance, rf power, pressure inside the chamber etc. are optimized systematically. Crystallization of the YCr0.5Mn0.5O3 bulk and thin films were characterized by X-ray diffractometer. Surface morphology was captured using scanning electron microscopy. Magnetic properties such as magnetic moment verse magnetic field and magnetic moment verses temperature of YCr0.5Mn0.5O3 thin films were characterized by physical property measurement system. High magnetic moment and sharp magnetic transition observed at 85 K. These results are favorable to spintronic applications.

Introduction

The study investigates the structural, morphological, and magnetic properties of YCr?.?Mn?.?O? thin films, a rare-earth transition-metal oxide belonging to the orthochromite family. These materials have attracted interest because of their magnetic ordering, weak ferromagnetism, and potential magnetoelectric/multiferroic applications. While YCrO? and related compounds have been extensively studied in bulk form, their thin-film properties remain comparatively less explored. Thin-film fabrication also provides opportunities for strain engineering and stabilization of novel material phases.

The YCr?.?Mn?.?O? ceramic target was prepared using a solid-state reaction method. High-purity Y?O?, Cr?O?, and Mn?O? powders were mixed, ground, pre-calcined at 1000°C, and finally calcined at 1100°C. The resulting powder was pressed into a 2-inch target and sintered at 1170°C for 12 hours.

Thin films were deposited on LAO and Pt/Si substrates using RF magnetron sputtering. Deposition parameters such as RF power, working pressure, oxygen concentration, substrate temperature, and target-to-substrate distance were varied to obtain uniform and crystalline films. The films were primarily investigated at substrate temperatures of 700°C and 850°C, with Ar/O? maintained at 50:50 and a working pressure of 10 mTorr.

Structural and Morphological Results

X-ray diffraction (XRD) analysis confirmed that the bulk YCr?.?Mn?.?O? powder formed the desired crystalline phase without significant impurity phases. For the thin films, lower-temperature or as-deposited samples showed weaker crystallinity or amorphous characteristics, whereas films deposited/annealed at higher temperatures exhibited improved crystallinity with an orthorhombic structure.

The crystallite size was estimated using the Scherrer equation:

D=βcosθkλ?

The estimated crystallite sizes were approximately 33 nm at 700°C and 45 nm at 850°C, demonstrating that increasing the deposition temperature promotes crystal growth.

SEM analysis further confirmed the temperature-dependent morphological evolution. Films deposited at 700°C showed randomly distributed grains, lower crystallization, and poor densification. In contrast, films deposited at 850°C exhibited more uniform grains, better packing density, and grain sizes of approximately 100 nm.

Magnetic Properties

Magnetic measurements were performed under magnetic fields of approximately ±5 T. The film deposited at 700°C exhibited a weak and unsaturated hysteresis loop, indicating relatively weak ferromagnetic behavior. This was attributed to its poorer crystallinity and less-developed grain structure.

The film deposited at 850°C demonstrated significantly enhanced magnetic behavior. Its magnetization increased with applied magnetic field, indicating a stronger ferromagnetic contribution and reduced antiferromagnetic behavior. Thus, improved crystallinity and morphology at higher deposition temperature were associated with enhanced magnetic properties.

Temperature-dependent magnetic measurements were performed from 0–400 K under an applied field of 100 Oe. A clear magnetic transition was observed at approximately 75 K for the 700°C film and 85 K for the 850°C film. The higher transition temperature and stronger magnetic response of the 850°C sample indicate that higher-temperature processing produces more favorable magnetic properties.

Overall Conclusion

The study demonstrates that deposition temperature strongly influences the structural, morphological, and magnetic properties of YCr?.?Mn?.?O? thin films. Increasing the temperature from 700°C to 850°C improves crystallinity, increases crystallite size, produces better grain morphology and densification, and enhances ferromagnetic behavior. The 850°C film also exhibits a higher magnetic transition temperature of approximately 85 K, compared with 75 K for the 700°C film.

Conclusion

Single phase YCr0.5Mn0.5O3 target was prepared by solid state method. Crystalline form of YCr0.5Mn0.5O3 thin film was successfully grown on Pt/Si substrates. XRD pattern of these films are well crystallized into orthorhombic structure as the temperature increases. Densified and uniformly distributed grains are grown for the films deposited at 850 oC. Excellent magnetic properties are exhibited for the films deposited at 850 oC which are useful for the spintronic devices.

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Copyright © 2026 A. Rambabu. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.