Role of stress/strain in tailoring the magnetic and transport properties of magnetic thin films and multilayers

Fuente: arXiv
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Main Authors: Dev, Arun Singh, Kumar, Dileep
Format: Preprint
Published: 2024
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author Dev, Arun Singh
Kumar, Dileep
author_facet Dev, Arun Singh
Kumar, Dileep
contents Magnetic anisotropy is a fundamental property of magnetic materials that determines the alignment of the spins along the preferential direction, called the easy axis of magnetization. Magnetic polycrystalline thin films offer several advantages over magnetic epitaxial thin films because of fabrication flexibility, higher coercivity and improved magnetic stability, higher magnetoresistance (useful in magneto-resistive devices such as magnetic field sensors and MRAM cells), cost-effectiveness and thermal stability, etc. In the case of polycrystalline thin films or multilayers, Magneto-crystalline anisotropy (MCA) is not expected due to the random orientation of grains. Therefore, understanding the origin of uniaxial magnetic anisotropy (UMA) is generally difficult and can't be understood in terms of crystal orientation. The origin of UMA in polycrystalline films is often related to the preparation conditions and substrate properties. In the present thesis, we have provided direct in-situ real-time evidence of the stress dependence of magnetic anisotropy through the multibeam optical stress sensor (MOSS) technique. Also, we have tuned the magnetic anisotropy in strength and direction using externally applied stress. To further increase the strength of the magnetic anisotropy, we have developed a new technique that creates a multilayer using a single magnetic material through sequential oblique and normal depositions. This oblique angle deposition technique also helps reduce the penetration of the top ferromagnetic layer inside the organic semiconductor layer in organic spin valve structures. We confirm our results through various in-situ (in UHV and HV) and ex-situ temperature-dependent conventional and unconventional structural, morphological, and magnetic measurements (both lab-based and synchrotron-based) that include MOKE, KERR, GIXRD, AFM, RHEED, and GISAXS, etc. measurements.
format Preprint
id arxiv_https___arxiv_org_abs_2405_00049
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Role of stress/strain in tailoring the magnetic and transport properties of magnetic thin films and multilayers
Dev, Arun Singh
Kumar, Dileep
Materials Science
Magnetic anisotropy is a fundamental property of magnetic materials that determines the alignment of the spins along the preferential direction, called the easy axis of magnetization. Magnetic polycrystalline thin films offer several advantages over magnetic epitaxial thin films because of fabrication flexibility, higher coercivity and improved magnetic stability, higher magnetoresistance (useful in magneto-resistive devices such as magnetic field sensors and MRAM cells), cost-effectiveness and thermal stability, etc. In the case of polycrystalline thin films or multilayers, Magneto-crystalline anisotropy (MCA) is not expected due to the random orientation of grains. Therefore, understanding the origin of uniaxial magnetic anisotropy (UMA) is generally difficult and can't be understood in terms of crystal orientation. The origin of UMA in polycrystalline films is often related to the preparation conditions and substrate properties. In the present thesis, we have provided direct in-situ real-time evidence of the stress dependence of magnetic anisotropy through the multibeam optical stress sensor (MOSS) technique. Also, we have tuned the magnetic anisotropy in strength and direction using externally applied stress. To further increase the strength of the magnetic anisotropy, we have developed a new technique that creates a multilayer using a single magnetic material through sequential oblique and normal depositions. This oblique angle deposition technique also helps reduce the penetration of the top ferromagnetic layer inside the organic semiconductor layer in organic spin valve structures. We confirm our results through various in-situ (in UHV and HV) and ex-situ temperature-dependent conventional and unconventional structural, morphological, and magnetic measurements (both lab-based and synchrotron-based) that include MOKE, KERR, GIXRD, AFM, RHEED, and GISAXS, etc. measurements.
title Role of stress/strain in tailoring the magnetic and transport properties of magnetic thin films and multilayers
topic Materials Science
url https://arxiv.org/abs/2405.00049