Magnetic property under the pressure and electrical transport behavior under the magnetic field for the perovskite manganite La0.7Ca0.3MnO3

Magnetic properties of La0.7Sr0.3MnO3 under the pressure and the transport property under the magnetic field

“…For the orthorhombic La 0.9 Ca 0.1 MnO 3 (T c = 191 K, P = 0), when P is in the range of 0~0.83 GPa, T c increases linearly with P with dT c /dP = 15.90 K/GPa. It can be seen that dT c /dP of LSMO is much smaller than that of La 0.7 Ca 0.3 MnO 3 59 and La 0.9 Ca 0.1 MnO 3. For La 0.7 Ca 0.3 MnO 3 , the average A-site ionic radius r A is less than 1.22 Å.…”

“…55 The results of neutron diffraction upon La 0.7 Sr 0.3 MnO 3 showed that when the pressure P increased from 0 to 7.5 GPa, the lattice parameter a decreased from 5.5038 to 5.4294 Å, and c decreased from 13.354 to 13.167 Å. 60 We also studied the magnetic properties of the orthorhombic La 0.7 Ca 0.3 MnO 3 (T c = 256 K, P = 0) 59 with the Pnma symmetry under the pressure. It was observed that, when P is in the range of 0~0.84 GPa, the average pressure coefficient of T c is dT c /dP = 15.47 K/GPa.…”

“…Moreover, the particle size also affects the dipolar field, 70 and hence the magnetization. The results of scanning electron microscopy of LSMO, La 0.7 Ca 0.3 MnO 3 59 and La 0.9 Ca 0.1 MnO 3…”

“…73,74 The quantum origin of magneto-crystalline anisotropy is the interaction between spin, orbit and lattice. 75 At the ambient pressure, in the paramagnetic region above T c (362 K), since the magnetic moment of Mn ions tends to be disordered, the anisotropic energy barrier distribution F(T) is 0; With the decrease in temperature, F(T) has a negative peak at 363 K. For La 0.7 Ca 0.3 MnO 3 59 and La 0.9 Ca 0.1 MnO 3 , this peak is not observed under the ambient pressure, but the negative peak appeared after the pressure is applied; such the negative peak may be due to the variation in anisotropy caused by the AFM coupling between ferromagnetic clusters, which will be further discussed in Figure 6. Subsequently, F(T) shows a positive peak at 361 K (close to T c ), due to the anisotropy change from the parallel arrangement of Mn ion magnetic moments around the ferromagnetic transition.…”

“…Recently, we reported the pressure effect on the magnetic properties of orthorhombic symmetric structured La 0.7 Ca 0.3 MnO 3 . 59 Compared with La 0.7 Ca 0.3 MnO 3 , Sr 2+ in La 0.7 Sr 0.3 MnO 3 has a larger ion radius than Ca 2+ in La 0.7 Ca 0.3 MnO 3 ; such the slight change produces the significant difference between La 0.7 Ca 0.3 MnO 3 and La 0.7 Sr 0.3 MnO 3 , even though they have the same Mn 3+ /Mn 4+ molar ratio. Specifically, La 0.7 Sr 0.3 MnO 3 has the rhombohedral structured with the R3c symmetry; it has the more perfect MnO 6 octahedron with the same Mn-O bond length and the same Mn-O-Mn bond angle, so there is no cooperative J-T distortion, resulting in the stronger Mn 3+ -O-Mn 4+ double-exchange and hence higher T c and magnetization.…”