Phase separation and stability in Sm_0.50Sr_0.50MnO₃: effects of cation dopants

Abstract

The Sm0.50Sr0.50MnO3 system has been studied with respect to identifying the various electronic and magnetic phases and the effects of introducing different cation dopants on these phases and their respective stabilities. Magnetic, resistive and thermoelectric studies have been performed as a function of temperature in Sm0.50Sr0.50MnO3, (Sm0.50Nd0.50)0.50Sr0.50MnO3 and Sm0.50(Sr0.50Ca0.50)0.50MnO3. The parent compound (Sm0.50Sr0.50MnO3) lies close to the ferromagnetic–antiferromagnetic (FM–AFM) phase boundary and the consequent effects of the dopants are explained in terms of the changes in the one electron bandwidth and the cation size variation and disorder. Below 130 K the ground state for Sm0.50Sr0.50MnO3 composition is seen to be a mixture of ferromagnetic and A-type antiferromagnetic phases. Partial substitution of a larger size cation (Nd) in place of Sm raises the ferromagnetic transition temperature while at the same time stabilizing the AFM phase. This latter trend is inferred from the differences in the hysteresis behaviour of the two systems and is explained in terms of the decrease of the size mismatch factor between cations. However, partial substitution of the smaller size cation (Ca) in place of Sr almost eliminates the ferromagnetic phase, leaving the system in a charge ordered state, which appears to be accompanied by the CE type of charge–orbital ordering, exhibiting extremely large values of resistivity.

Correlating melting and collapse of charge ordering with magnetic transitions in La 0.5-x Pr x Ca 0.5 MnO 3

“…3(b). This sharp increase in the M(H) can be explained by the melting of large fraction of major AFM phase into FM phase [31].…”

Magnetic phase diagram of nanosized half-doped manganites: role of size reduction

“…In this paper, the magnetic properties of the nanosized Nd 0.5 Ca 0.5 MnO 3 (NCMO) and Sm 0.5 Sr 0.5 MnO 3 (SSMO) are investigated in detail by magnetometry and ESR spectroscopy and the above issues are focused on. It is well known that the bulk NCMO shows a robust CO transition at T CO ∼ 250 K and an AFM ordering at T N ∼ 150 K, whereas the bulk SSMO exhibits a weak CO transition around 200 K and a FM ordering below T C ∼ 150 K [28][29][30] (also see Fig. 1(b) and (c), respectively).…”

Electron-doped Sm1−xSrxMnO3 perovskite manganites: Crystal and magnetic structures and physical properties

“…Depending on the actual concentration x of the element A, the physical properties of manganites can vary noticeably with a change in the temperature and external magnetic field, which, in turn, can induce sequences of phase transitions [1][2][3]. The present report is a continuation of our systematic physical investigation of the Sm 1Àx Sr x MnO 3 manganites [4][5][6][7][8][9], which are of considerable research interest [3,[10][11][12]. Owing to the large difference between the ionic radii of samarium and strontium the Sm 1Àx Sr x MnO 3 manganites exhibit, with a rather typical behavior for manganites, unique physical properties with a vivid manifestation of interactions between the electron, phonon, and magnetic subsystems.…”