Magnetic relaxation and magnetization field dependence measurements in La0.5Ca0.5MnO3

Abstract

We reported a systematic change in the average magnetic relaxation rate, after the application and removal of a 5 T magnetic field, in a polycrystalline sample of La 0.5 Ca 0.5 MnO 3 . Magnetic relaxation measurements and magnetization versus field curves were taken from 10 K to 160 K. The long time behavior of the relaxation curves was approximately logarithmic in all cases.Charge ordering compounds have a large variation of resistivity and magnetization as a function of temperature and magnetic field 1,2 .A representative example, La 0.5 Ca 0.5 MnO 3 has a paramagnetic-ferromagnetic transition around 265 K and a ferromagnetic-antiferromagnetic (FM-AFM) phase transition at 160 K 3 . Accompanying the FM-AFM transition there is also a charge disordered to a charge ordered phase transition 3 .Polycrystalline samples of La 0.5 Ca 0.5 MnO 3 were prepared by the solid-state method described elsewhere 4 . X-ray diffraction measurements pointed out high quality samples. Magnetization measurements were done with a standard MPMS-5S SQUID magnetometer. The relaxation measuring procedure was the following: first, the sample was heated to 400 K in zero magnetic field; second, the remanent magnetic field in the solenoid of the SQUID magnetometer was set to zero; third, the sample was cooled down to the working temperature

Study of magnetic and specific heat measurements at low temperatures in Nd0.5Sr0.5MnO3, Nd0.5Ca0.5MnO3

“…In two previous reports 3,4 we showed that polycrystalline samples of La 0.5 Ca 0.5 MnO 3 and Nd 0.5 Sr 0.5 MnO 3 also presented an unusual magnetic relaxation behavior after applying and turning off a 5 T magnetic field. Here, we briefly report specific heat measurements at low temperatures and zero magnetic field for Although it is tenting to establish a straight forward correlation between the intrinsic 10 .…”

Thermal hysteresis in electrical transport of charge ordered La0.5Ca0.5MnO3 manganites

“…With increase in x, La 1 − x Ca x MnO 3 shifts from insulating to metallic behaviour. But at x = 0.5, where Mn 3+/4+ ratio is 1:1, charge ordered (CO) insulating state [6,7] occurs where manganese ions align themselves in an ordered pattern and thus hampering the movement/hopping of conduction electrons. However, on application of magnetic field, this CO state melts down giving rise to huge magnetoresistance (MR) below T CO [4].…”

Specific heat at low temperatures and magnetic measurements inNd0.5Sr0.5MnOLópez1, Lima2, Lisboa‐Filho3 et al. 2002Phys. Rev. B447190View full textAdd to dashboardCite

“…6 We have shown that polycrystalline samples of La 0.5 Ca 0.5 MnO 3 and Nd 0.5 Sr 0.5 MnO 3 presented an unusual magnetic relaxation behavior close to each critical temperature. 7,8 However, a clear understanding of all these features has not been reached yet. An alternative to a bulk characterization like magnetization would be to perform specific-heat measurements.…”