Interplay of structural, magnetic and transport properties in thelayered Co-based perovskite LnBaCo 2 O 5 (Ln = Tb, Dy, Ho)

Crystal structure and structural phase transitions in the GdBaCo2O5.0cobaltite

“…[1][2][3][4] It may also happen, on the other hand, that electronic and magnetic-phase transitions are associated to somewhat hardly detectable structural distortions that nevertheless may imply important symmetry changes. This is just the case of the cobaltites of general formula LnBaCo 2 O 5+δ , where 0 < δ < 1 and Ln may be a trivalent lanthanide ion or yttrium.…”

“…This is just the case of the cobaltites of general formula LnBaCo 2 O 5+δ , where 0 < δ < 1 and Ln may be a trivalent lanthanide ion or yttrium. Such compounds have raised in the last decade a great deal of interest due to their intriguing magnetic and transport properties, [4][5][6][7][8] which can furthermore be varied as a function of temperature [7][8][9] or even pressure. 7 Recently, these compounds turned out to be attractive also for the development of new intermediatetemperature solid oxides fuel cells (IT-SOFC).…”

“…In general the possibility of tuning with great accuracy the effective oxygen content 12 and/or selecting lanthanide ions of different radii 13 within the LnBaCo 2 O 5+δ structure, provides the opportunity to control several macroscopic key features such as resistivity, thermoelectric power, and magnetoresistance (MR). 12,[14][15][16][17] Approximately a decade ago, the crystal structure of oxygen-deficient LnBaCo 2 O 5.0 (Ln = Y, 18 Tb, 4 Dy, 4 Ho, 4 and Nd 19 ) compounds was accurately determined by powderneutron diffraction studies, concluding that they are all paramagnetic with tetragonal space group P4/mmm above the Néel temperature (T N ), that ranges from 330 to 380 K, depending on Ln 3+ ionic radii. Concerning the Ln = Gd compound, in particular, a reasonable estimate of T N ≈ 350 K comes from both magnetic 12 and shear modulus 20 measurements.…”

Tunable strain effect and ferroelectric field effect on the electronic transport properties of La0.5Sr0.5CoO3 thin films

“…In comparison with the lattice constants of the LSCO bulk, the decrease in the lattice We measured the temperature dependence of the resistance for the LSCO film when the PMN-PT substrate was in the unpoled state and showed the results in the inset (a) of ) substrates with in-plane tensile strain, the resistance of the LSCO film increases with decreasing temperature from 300 K, which is in contrast to the metallic conductivity (i.e., dR=dT > 0) of the bulk LSCO single crystals. 6 The strain-induced static Jahn-Teller-type deformation of the CoO 6 units may provide a localization mechanism 10,25 for understanding the insulating behavior (dR=dT < 0) of the film. Besides, the insulating behavior could be resulted from the incorporation of oxygen vacancies which interrupt the Co-O-Co electron hopping networks, causing semiconducting behavior of the resistance.…”

Magnetic Structures and Spin States of NdBaCo2O5.5

“…[5][6][7][8] For the combinations of large Ba 2+ ions and relatively small R 3+ ions, the system forms several kinds of the oxygen-deficient perovskite structure, in which the oxygen vacancies are ordered, [9][10][11][12][13][14][15][16][17] and a various physical behaviors are expected. However, only the restricted information is available on both the structural properties and the electronic properties.…”