Pressure induced anomalous magnetic behaviour in nanocrystalline YCrO₃ at room temperature

Abstract

High pressure behaviour of nanocrystalline YCrO is investigated up to 10 GPa using electrical, magnetic, synchrotron x-ray diffraction and Raman spectroscopy measurements. High pressure dielectric constant measurements show a sharp peak at 4.5 GPa, though the sample is found to be in ferroelectric phase up to the highest pressure of our study from piezoelectric current measurements. X-ray diffraction measurements show absence of any structural phase transition, however anomalies are observed in the unit cell structural parameters at about 4.3 GPa and the Y-atom position shows a maximum shift at the same pressure. In the absence of any structural transition, anomalous behaviour of relevant Raman modes with minimum in the Raman band width at about same pressure indicate towards a spin-phonon interaction. AC magnetic measurements in the toroid anvil cell show an anomalous enhancement of magnetic moment above 4 GPa indicating a collective magnetic response of nanoparticles.

High‐pressure structural investigation on lead‐free piezoelectric 0.5Ba(Ti0.8Zr0.2)O3 ‐ 0.5(Ba0.7Ca0.3)TiO3

“…The TA apparatus is calibrated using Bi I-II and Yb hcp-bcc transitions at 2.65 GPa and 4 GPa, respectively. 35 The sample assembly is prepared and the frequency-dependent capacitance is measured as described by Jana et al 27 The dielectric constant (K) is calculated using the expression, C = Kϵ 0 (A/d), where ϵ 0 is the permittivity of the free space, C is the capacitance, A is the area of the copper plate, and d is the thickness of the sample pellet.…”

“…The volume compression can lead to change in internal strain giving rise to several changes in the physical properties of the material leading to novel phase transitions that may include structural, electronic transitions etc. [27][28][29] BCZT, which is a solid solution of BZT-BCT, hold all the properties of its parent material BaTiO 3 along with the effect of doping on it. Therefore, the present manuscript focuses on high-pressure Raman spectroscopy, x-ray diffraction, and dielectric measurements of BCZT to study phase transitions, which modify its dielectric properties and piezoelectric nature.…”

Tuning magnetic and optical properties through strain in epitaxial LaCrO3 thin films

“…The theory results also suggest that the optical band gap of RCrO3 can be decreased by as large as 0.2 eV by judiciously choosing the strain conditions [21]. However, despite the theoretical predictions, available experimental evidences pertaining to the effect of epitaxial strain on the magnetic and optical properties of RCrO3 are highly limited [17,28,32]. Direct experimental observation of strain-tunability of the RCrO3 perovskites can offer new opportunities to tailor their physical properties and expand practicality for various functional applications.…”

“…Recent observations on tuning the structure, magnetic and optical properties of bulk RCrO3 by chemical-strain, misfit-strain and hydrostatic pressure have attracted significant attention towards the functional applications of this class of materials [26][27][28][29][30][31]. The lattice structure, net magnetic moment, magnetic ordering temperature, and optical band-gap can be tuned through the change of internal strain in RCrO3 lattice, either by external applied pressure or chemical strain [21,26,27,31].…”

“…The lattice structure, net magnetic moment, magnetic ordering temperature, and optical band-gap can be tuned through the change of internal strain in RCrO3 lattice, either by external applied pressure or chemical strain [21,26,27,31]. Enhanced magnetization and reduced optical band gap are observed due to the application of hydrostatic pressure and chemical strain, respectively [27,28,30]. Theoretical studies reports that the epitaxial-strain modifies antipolar displacements, Cr-O-Cr bond angles, Cr-O bond lengths and oxygen octahedral tilt within the lattice symmetry (Pbnm), which significantly affect the magnetic behavior of RCrO3 [26].…”