Engineering the magnetocaloric properties of PrVO3 epitaxial oxide thin films by strain effects

Abstract

Combining multiple degrees of freedom in strongly-correlated materials such as transition-metal oxides would lead to fascinating magnetic and magnetocaloric features. Herein, the strain effects are used to markedly tailor the magnetic and magnetocaloric properties of PrVO3 thin films. The selection of appropriate thickness and substrate enables us to dramatically decrease the coercive magnetic field from 2.4 T previously observed in sintered PVO3 bulk to 0.05 T for compressive thin films making from the PrVO3 compound a nearly soft magnet. This is associated with a marked enhancement of the magnetic moment and the magnetocaloric effect that reach unusual maximum values of roughly 4.86 µB and 56.8 J/kg K in the magnetic field change of 6 T applied in the sample plane at the cryogenic temperature range (3 K), respectively. This work strongly suggests that taking advantage of different degrees of freedom and the exploitation of multiple instabilities in a nanoscale regime is a promising strategy for unveiling unexpected phases accompanied by a large magnetocaloric effect in oxides.

Assessment of near Pr2/3Sr1/3MnO3 oxide in magnetic cooling

“…From a practical point of view, this value is comparable with the maximum COP that can be reached by a conventional refrigerator (Sari and Balli, 2014). However, larger COP can be obtained by inducing large thermal effects in the Pr 0.6 Sr 0.4 MnO 3 regenerator, which would be achieved by subjecting the latter to high magnetic fields and/or strain effects (Bouhani et al, 2020). From obtained results, it is clearly observed that the coefficient of performance for Pr 0.6 Sr 0.4 MnO 3 is lower than that of Gd (Chiba et al, 2014), under similar working conditions.…”

“…For example, the simultaneous application of several excitations such as magnetic field, electrical field and strain effects would lead to unusual MCEs. In a recently reported work, Bouhani et al (Bouhani et al, 2020) were able to induce in PrVO 3 thin films a magnetic entropy change that approaches the theoretical limit when subjecting them to strain effects. Consequently, this would open the way for boosting the MCE in the family of strongly correlated materials such as RMnO 3 manganites.…”

Photoresponsive Polymers with Aggregation-Induced Emission

“…Compared with traditional photothermal materials, photothermal AIE materials are more ideal for desalination because the molecular rotors and/or vibrators in AIE moieties are favorable to boost the photothermal conversion efficiency. 109 In 2020, Gu and co-workers synthesized a photothermal molecule (7) containing AIEgens with broad absorption from 300 to 1600 nm upon aggregation. A photophysical responsive polymer (PU-7) was further constructed by doping molecule 7 into polyurethane (PU).…”

“…Smart materials are new types of functional materials that can perceive external stimulations and then judge and respond appropriately by themselves. , They are one of the most important directions for the development of modern intelligent materials in the information age . Although there is still no unified definition, smart materials are generally called responsive materials with the following characteristics: (1) perceptiveness, i.e., able to detect and recognize the intensity of external or internal stimuli, such as electricity, light, heat, magnetism, mechanical force, solvent, pH, chemistry, nuclear radiation, etc., (2) targeted conversion, i.e., able to convert the input stimulus signal into the targeted output response signal through specific mechanisms/pathways, (3) responsiveness, i.e., capable of responding to stimuli through timely changes in physical/chemical properties. − Among all these stimuli, light is the most unique stimulu due to its special properties such as precise stimulation and response, remote nonintrusive control, and environmental friendliness. Photoresponsive materials undergo either a photochemical or photophysical mechanism to convert the light stimulation into a chemistry reaction, sound, light, heat, electricity, force, and other forms of energy .…”

On the electronic and magnetic properties of RVO3 (R = Er, Ho, Y, Lu) vanadates: first principles study

“…K) for a field change of 1.4 T. In addition, the HoVO3 compound shows a giant conventional MCE of 17.2 J/kg K for 7 T without thermal and magnetic hysteresis close to THo. In addition, Bouhani et al [27] showed that the magnetocaloric effect of PrVO3 thin films reaches unusual maximum values of 56.8 J/kg K with the magnetic field change of 6 T applied in the sample plane over the cryogenic temperature range close to 3 K. On the other hand, S. Kumari et al [29] have used GGA+U approximation to perform an ab-initio selfconsistent computation of the electronic structure of LaVO3 and YVO3, revealing semiconducting behavior in the electronic band structure and density of states for both compounds with band gaps of 1.1 eV and 1.2 eV, respectively. However, to our knowledge similar investigations of RVO3 with magnetic rare earth elements have not been reported up to know which is due more probably to their complicated structure and the lack of significant experiment findings such as band gap values.…”