Exchange bias–like behavior in La0.75Sr0.25MnO3 / LaNiO3 multilayers

J. C. ROJAS SÁNCHEZ; M. GRANADA; L. B. STEREN

Buenos Aires, Argentina

Workshop; At the Frontiers of Condensed Matter IV; 2008

Magnetoresistive systems have been widely studied due to their potential application in spintronics devices. In particular, the development of oxides-based devices has attracted much interest lately. In a previous work, we have shown that trilayers composed of La0:75Sr0:25MnO3 (LSMO) ferromagnetic electrodes and LaNiO3 (LNO) spacers present a giant magnetoresistance effect [1]. These interesting results appear to indicate that this system is promising for magnetoelectronic devices. In this work we will show that the magnetic properties of these structures present an unexpected behaviour that makes them very interesting from a fundamental point of view also. A detailed study of the magnetism of LSMO/LNO structures reveals that these multilayers exhibit an exchange-bias (EB) anisotropy in spite of the fact that the LNO is a Pauli paramagnet. 0:75Sr0:25MnO3 (LSMO) ferromagnetic electrodes and LaNiO3 (LNO) spacers present a giant magnetoresistance effect [1]. These interesting results appear to indicate that this system is promising for magnetoelectronic devices. In this work we will show that the magnetic properties of these structures present an unexpected behaviour that makes them very interesting from a fundamental point of view also. A detailed study of the magnetism of LSMO/LNO structures reveals that these multilayers exhibit an exchange-bias (EB) anisotropy in spite of the fact that the LNO is a Pauli paramagnet. Bilayers and multilayers with different LNO thickness have been grown by magnetron dc sputtering on crystalline (001) SrTiO3 substrates. X-ray diffraction measurements indicate that the samples grow highly textured in the (001) direction [2]. The comparison of magnetization loops measured at T=5K with different cooling conditions proof that our samples present exchange bias. A difference of the coercive eld in the curves measured in zero eld cooling (ZFC) and eld cooling (FC) experiments is observed. The FC experiments were carried out after cooling the samples from 250K to 5K with different applied elds ( 1 kOe > H < 4 kOe). The temperature dependence of the exchange bias effect has been also studied. Preliminary magneto-transport measurements, performed in the same experimental conditions, will be also  shown. [1] M. Granada, J. C. Rojas Sáanchez, L. B. Steren, Appl. Phys. Lett. 91, 072110 (2007). [2] J. C. Rojas Sáanchez, M. Granada, L. B. Steren, I. Mazzaro, D. H. Mosca, Appl. Surf. Sci. 254, 219 (2007). J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. [2] J. C. Rojas Sáanchez, M. Granada, L. B. Steren, I. Mazzaro, D. H. Mosca, Appl. Surf. Sci. 254, 219 (2007). J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. [2] J. C. Rojas Sáanchez, M. Granada, L. B. Steren, I. Mazzaro, D. H. Mosca, Appl. Surf. Sci. 254, 219 (2007). J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. Preliminary magneto-transport measurements, performed in the same experimental conditions, will be also  shown. [1] M. Granada, J. C. Rojas Sáanchez, L. B. Steren, Appl. Phys. Lett. 91, 072110 (2007). [2] J. C. Rojas Sáanchez, M. Granada, L. B. Steren, I. Mazzaro, D. H. Mosca, Appl. Surf. Sci. 254, 219 (2007). J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. [2] J. C. Rojas Sáanchez, M. Granada, L. B. Steren, I. Mazzaro, D. H. Mosca, Appl. Surf. Sci. 254, 219 (2007). J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. [2] J. C. Rojas Sáanchez, M. Granada, L. B. Steren, I. Mazzaro, D. H. Mosca, Appl. Surf. Sci. 254, 219 (2007). J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. Preliminary magneto-transport measurements, performed in the same experimental conditions, will be also  shown. [1] M. Granada, J. C. Rojas Sáanchez, L. B. Steren, Appl. Phys. Lett. 91, 072110 (2007). [2] J. C. Rojas Sáanchez, M. Granada, L. B. Steren, I. Mazzaro, D. H. Mosca, Appl. Surf. Sci. 254, 219 (2007). J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. [2] J. C. Rojas Sáanchez, M. Granada, L. B. Steren, I. Mazzaro, D. H. Mosca, Appl. Surf. Sci. 254, 219 (2007). J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. [2] J. C. Rojas Sáanchez, M. Granada, L. B. Steren, I. Mazzaro, D. H. Mosca, Appl. Surf. Sci. 254, 219 (2007). J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. Preliminary magneto-transport measurements, performed in the same experimental conditions, will be also  shown. [1] M. Granada, J. C. Rojas Sáanchez, L. B. Steren, Appl. Phys. Lett. 91, 072110 (2007). [2] J. C. Rojas Sáanchez, M. Granada, L. B. Steren, I. Mazzaro, D. H. Mosca, Appl. Surf. Sci. 254, 219 (2007). J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. [2] J. C. Rojas Sáanchez, M. Granada, L. B. Steren, I. Mazzaro, D. H. Mosca, Appl. Surf. Sci. 254, 219 (2007). J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. [2] J. C. Rojas Sáanchez, M. Granada, L. B. Steren, I. Mazzaro, D. H. Mosca, Appl. Surf. Sci. 254, 219 (2007). J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. [2] J. C. Rojas Sáanchez, M. Granada, L. B. Steren, I. Mazzaro, D. H. Mosca, Appl. Surf. Sci. 254, 219 (2007). J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET. J.C. Rojas Sáanchez and M. Granada acknowledge a fellowship from CONICET. L.B.Steren is a member of CONICET.