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

J. C. ROJAS SANCHEZ, M. GRANADA, G. LEYVA, L.B. STEREN

Virgin Islands, USA

Congreso; 2009 Villa Conference on Complex Oxide Heterostructures,; 2009

&lt;!-- /* Font Definitions */ @font-face {font-family:SimSun; panose-1:2 1 6 0 3 1 1 1 1 1; mso-font-alt:&#23435;&#20307;; mso-font-charset:134; mso-generic-font-family:auto; mso-font-format:other; mso-font-pitch:variable; mso-font-signature:1 135135232 16 0 262144 0;} @font-face {font-family:"@SimSun"; panose-1:0 0 0 0 0 0 0 0 0 0; mso-font-charset:134; mso-generic-font-family:auto; mso-font-format:other; mso-font-pitch:variable; mso-font-signature:1 135135232 16 0 262144 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0in; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:SimSun;} p.AbstractBooktext, li.AbstractBooktext, div.AbstractBooktext {mso-style-name:"AbstractBook text"; margin-top:0in; margin-right:0in; margin-bottom:3.0pt; margin-left:0in; text-align:justify; text-indent:26.95pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Times New Roman"; mso-fareast-font-family:SimSun; mso-fareast-language:RU;} @page Section1 {size:8.5in 11.0in; margin:1.0in 1.25in 1.0in 1.25in; mso-header-margin:.5in; mso-footer-margin:.5in; mso-paper-source:0;} div.Section1 {page:Section1;} --&gt; 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 [1]. 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. [2]   In the present work we show that the magnetic properties of theses structures present unexpected behaviour that makes them very interesting from a fundamental point of view. A detailed study of the magnetism of LSMO/LNO structures reveals that these multilayers exhibit an exchange-bias anisotropy in spite of the fact that 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. [3] The relative shift of the magnetization loops along the magnetic field axis measured  at low temperatures and different cooling conditions is the main evidence of an exchange-bias like behaviour.  Moreover, we measure different coercive fields, when measured in zero-field-cooling (ZFC) and field-cooling (FC) experiments. The FC experiments were carried out after cooling the samples from 250K to 5K with different applied fields (1kOe < H < 4kOe). 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 presented.