Understanding thermomagnetic hysteresis in La1−x−yPryCaxMnO3 thin films. (5th June 2017)

• Record Type: Journal Article
• Authors: Yadav, Akash; Singh, Sandeep; Vashist, Amit; Sharma, Gyanendra; Siwach, P K; Singh, H K
• Is Part Of: Materials research express. Volume 4:Number 6(2017)
• Publication Date: 2017-06-05
• Subjects: thermomagnetic hysteresis -- insulator–metal transition temperature -- phase separation -- magnetic liquid; Materials science -- Research -- Periodicals; Materials science -- Periodicals; 620.11
• DOI: 10.1088/2053-1591/aa7019
• Languages: English
• ISSNs: 2053-1591

Abstract

Abstract: The present work reports the scaling behaviour of thermomagnetic hysteresis in temperature and magnetic field dependent resistivity [( ρ – T ) and ( ρ – H )] measured during cooling/warming and H increasing/decreasing cycles in single crystalline La0.21 Pr0.42 Ca0.37 MnO3 thin films. The zero-magnetic field ( H = 0) insulator–metal transition temperature (IMT) measured in warming cycle T IM W ~ 166 K is higher than that in the cooling cycle T IM C = 128 K and the difference between them shrinks as H is increased. The two IMTs scale with H as T IM = T IM 0 + β H α . Here T IM 0 is the H -independent contribution, and the constants, pre-factor β and exponent α determine the magnetic field dependent part. The ρ – T loop area ( A T ) diminishes with the increasing H as the magnetic liquid is extremely unstable with respect to external H ( H < 30 kOe) and consequently A T shows an exponential decay given by A T = A T 0 e − Γ H . Here, A T 0 is the zero-field normalized area and Γ is a constant related to the degree of phase separation. The analysis of the isothermal ρ – H loop area, which increases with H shows scaling behaviour of the type A ( H ) = A H ( H − H IM ) η . Here, the constant H IM corresponds to the magnetic field that induces AFMI to FMM phase transition and decreases with temperature, while the exponent ' η ' measures the degree of phase separation. The value of η is found to be temperature dependent and hence related to the relative fraction of the two coexisting phases.