Influence of the dimensionality of the structure and the nature of the rare earth on the magneto-transport properties of Nd1-xSr1+xCoO4 (0 ≤ x ≤ 0.30)

• Published in: Journal of alloys and compounds 2007-06, Vol.437 (1-2), p.64-70
• Main Authors: SANCHEZ-ANDUJAR, M, CASTRO-COUCEIRO, A, RIVAS-MURIAS, B, MIRA, J, RIVAS, J, SENARIS-RODRIGUEZ, M. A
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Conductivity phenomena in semiconductors and insulators; Electronic transport in condensed matter; Exact sciences and technology; Galvanomagnetic and other magnetotransport effects; Magnetic properties and materials; Physics; Spin arrangements in magnetically ordered materials (including neutron and spin-polarized electron studies, synchrotron-source x-ray scattering, etc.)
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2006.07.095

We report the magneto-transport properties of the layered mixed oxides Nd1-xSr1+xCoO4 (0 < =x < =0.3) compounds. These materials are found to evolve towards an anomalous 'cluster-glass' like behavior as x increases. The onset of the ferromagnetic order in the bidimensional phase is seen to occur in the x=0.30 sample at Tc(2D){approximately equal to}125K, followed by a blocking process around TB (2D){approximately equal to}55K. In addition, present in the magnetic response of these materials is the paramagnetic contribution coming from the Nd3+ ions mueff-Nd3+=3.62muB together with the signal coming from a minority perovskite phase, that is nevertheless not detected by powder X-ray diffraction. From the electrical point of view these materials are semiconducting and their resistivitiy decreases upon doping. In addition, at low temperatures T < 25K, these compounds show magnetoresistance. The highest effect is found for the sample x=0.3 that shows a magnetoresistance MR=-17% at T=10K under a field Hmax=50kOe.