Influence of structure defects on functional properties of magnetoresistance (Nd0.7Sr0.3)1−xMn1+xO3 ceramics

Expansion of the multifunctionality in off-stoichiometric manganites using post-annealing and high pressure: physical and electrochemical studies

“…2,23,[25][26][27][28] In addition, a change in the content of Mn in the A-and Bsites by the substitution of other ions, creation of cation vacancies V (c) B or introduction of overstoichiometric manganese also strongly influences the magneto-transport properties of manganites. 2,23,25,26,[28][29][30][31][32] Introducing excess Mn in the A-and/ or B-positions has a number of advantages since it brings to the completeness of the B-sublattice due to the existence of V (c) B vacancies and significantly improves the magneto-resistance effect without lowering T C ; [33][34][35][36] increases the metal-insulator temperature; 28 enhances transport properties and the FM metallic state due to the appearance of Mn 2+ ions in the A-sites, which have a half-filled conduction band crossing the Fermi level, and causes the multiple DE. 23 It also increases the T C and MCE, for example, in La 0.67 Ca 0.33 Mn 1+d O 3 nanopowders with ÀDS M = 2.94 J kg À1 K À1 (5 T) at T C = 240 K for d = 0 and ÀDS M = 2.90 J kg À1 K À1 (5 T) at T C = 248 K for d = 0.05; 37 in La 0.8Àx Ag 0.2 Mn 1+x O 3 bulk with ÀDS M = 2.40 J kg À1 K À1 (1 T) at T C = 300 K for x = 0, 38 and ÀDS M = 2.46 J kg À1 K À1 (1 T) at T C = 271 K for x = 0.1, 3 and in La 0.8Àx Ag 0.2 Mn 1+x O 3 nanopowders with ÀDS M = 0.96 J kg À1 K À1 (2 T) at T C = 306 K for x = 0, 39 and ÀDS M = 2.03 J kg À1 K À1 (1 T) at T C = 308 K for x = 0.2.…”

Observation of enhanced magnetic entropy change near room temperature in Sr-site deficient La0.67Sr0.33MnO3 manganite

“…The increase in unit cell volume of Sr-site decient compounds can be related to the decreasing concentration of oxygen due to the formation of anionic vacancies and the increase in radius of the decient Srsite. 37,48,49,59 The presence of oxygen vacancies is compensated by a reduction in the average valence of manganese ions. This leads to the reduction of some Mn 4+ to Mn 3+ and Mn 3+ to Mn 2+ .…”

Smart magnetic nanopowder based on the manganite perovskite for local hyperthermia

“…An increase in the temperature range of the magnetic phase transition is associated with both the appearance of local antiferromagnetic interactions caused by the Jahn-Teller electronphonon interaction with orthorhombic distortions, 30 and the magnetic inhomogeneity of the local environment of manganese as a result of the presence of cation V (c) and anion V (a) vacancies. 31,32 Superstoichiometric manganese is an excess manganese, for which the lling factor of the B-position in the molar formula exceeds one. Using NMR 55 Mn method, 31 39 Therefore, the nonstoichiometric La 0.6 Ag 0.2 Mn 1.2 O 3 composition with an increased content of super-stoichiometric manganese is considered here as the basis for the production of smart magnetic nanopowder for local hyperthermia.…”

“…31,32 Superstoichiometric manganese is an excess manganese, for which the lling factor of the B-position in the molar formula exceeds one. Using NMR 55 Mn method, 31 39 Therefore, the nonstoichiometric La 0.6 Ag 0.2 Mn 1.2 O 3 composition with an increased content of super-stoichiometric manganese is considered here as the basis for the production of smart magnetic nanopowder for local hyperthermia. In addition, on the toxicity of the investigated nanopowder, it should be added that the manganite perovskite nanoparticles show a better colloidal stability, good biocompatibility with cell lines and do not have toxic effects.…”