Piezomagnetic devices based on antiperovskite nitride thin films
File(s)
Author(s)
Zou, Bin
Type
Thesis
Abstract
Piezomagnetic coupling properties of manganese-based (Mn-based) nitride antiperovskites, Mn3XN (X=Ni, Ga, Sn), offer control of magnetism by electric field. This study suggests a device structure consisting of antiferromagnetic and ferroelectric/piezoelectric materials that can induce a net magnetisation in the antiferromagnetic material Mn3XN by means of a physical effect termed the piezomagnetic effect.
In this study, epitaxial thin films of Mn3XN were deposited on different single-crystal substrates. The research results show a clear correlation between the induced magnetisation and biaxial strain, compressive or tensile, given by the lattice mismatch between film and substrate. The induced magnetisation increases with the increase of the biaxial strain. Also, the Néel temperature (TN) of the Mn3NiN film is found to be strongly dependent on the biaxial strain. A change in TN of approximately 60 K is achieved by a biaxial strain of ±2.5%. In addition, the largest in-plane saturation magnetisation of 0.38 B/f.u. is obtained from the Mn3NiN film. The same saturation magnetisation is acquired in Mn3GaN film, whereas high saturation magnetisation of 0.6 B/f.u. is achieved in Mn3SnN film under a compressive strain of -0.18%.
Mn3NiN piezomagnetic device demonstrates the deterministic switching of magnetisation via electric field at low temperature, even in the absence of an external magnetic field. A large magnetocapacitance (MC) effect of 1400% is found in the Mn3GaN piezomagnetic device with respect to a DC bias of -1.5 V and a magnetic field of 7 T. The large MC effect originates from the piezomagnetic effect provided by the strained antiferromagnetic layer MGN induced by the underlying ferroelectric layer BST under the DC electric field.
The piezomagnetic effect is experimentally demonstrated, particularly in heterostructure devices. The work demonstrates the realisation of modulation of magnetic moments by the electric field by means of the piezomagnetic effect in conjunction with the ferroelectric effect.
In this study, epitaxial thin films of Mn3XN were deposited on different single-crystal substrates. The research results show a clear correlation between the induced magnetisation and biaxial strain, compressive or tensile, given by the lattice mismatch between film and substrate. The induced magnetisation increases with the increase of the biaxial strain. Also, the Néel temperature (TN) of the Mn3NiN film is found to be strongly dependent on the biaxial strain. A change in TN of approximately 60 K is achieved by a biaxial strain of ±2.5%. In addition, the largest in-plane saturation magnetisation of 0.38 B/f.u. is obtained from the Mn3NiN film. The same saturation magnetisation is acquired in Mn3GaN film, whereas high saturation magnetisation of 0.6 B/f.u. is achieved in Mn3SnN film under a compressive strain of -0.18%.
Mn3NiN piezomagnetic device demonstrates the deterministic switching of magnetisation via electric field at low temperature, even in the absence of an external magnetic field. A large magnetocapacitance (MC) effect of 1400% is found in the Mn3GaN piezomagnetic device with respect to a DC bias of -1.5 V and a magnetic field of 7 T. The large MC effect originates from the piezomagnetic effect provided by the strained antiferromagnetic layer MGN induced by the underlying ferroelectric layer BST under the DC electric field.
The piezomagnetic effect is experimentally demonstrated, particularly in heterostructure devices. The work demonstrates the realisation of modulation of magnetic moments by the electric field by means of the piezomagnetic effect in conjunction with the ferroelectric effect.
Version
Open Access
Date Issued
2025-08-31
Date Awarded
01/02/2026
License URL
Advisor
Petrov, Peter
Alford, Neil
Publisher Department
Department of Materials
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)