Journal of Magnetism and Magnetic Materials 237 (2001) 61–68 Substrate dependence of magnetic properties of La 0.67 Ca 0.33 MnO 3 films G. Campillo a,1 , A. Berger a, *, J. Osorio a,1 , J.E. Pearson a , S.D. Bader a , E. Baca b , P. Prieto b a Materials Science Division, Argonne National Laboratory, Argonne, IL 60439, USA b Departamento de F! ısica, Universidad del Valle, Cali, A.A. 25360, Colombia Received 6 April 2001; received in revised form 18 July 2001 Abstract We investigate the magnetic properties of 200-nm thick La 0.67 Ca 0.33 MnO 3 films, which were grown under identical conditions onto five single crystal substrates: SrTiO 3 (0 0 1), LaAlO 3 (0 0 1), MgO(0 0 1), NdGaO 3 (0 0 1) and Si(1 1 1). The films exhibit a strong substrate dependence of the magnetic properties, including the coercive field, remanent magnetization and Curie temperature T C : The T C distribution was determined for each film. The upper cut-off value for the distribution is found to be virtually identical in all samples, even though the distribution width itself varies by almost an order of magnitude. The results are attributed predominantly to the degree of sample homogeneity, and are discussed in terms of strain-induced growth mode differences. r 2001 Elsevier Science B.V. All rights reserved. Keywords: Manganites; Thin films; Epitaxial strain; Magnetic order; Phase transitions, Curie temperature 1. Introduction Manganite materials have received considerable attention since the discovery of the colossal magnetoresistance effect (for a recent review, see, for example, Ref. [1]). One area of particular interest is that of epitaxially grown films. The interplay between substrate and film allows the modification of properties and can even enhance the magnetoresistive effect [2,3]. There are two mechanisms by which substrates modify film properties. The first is associated with the lattice distortion of epitaxially grown, pseudomorphic films. Here, the substrate induces a biaxial strain in the film that alters the physical properties [4–14]. For instance, the magnetocrystalline anisotropy has been found to be strongly modified in such films with dramatic consequences for the magnetic and magnetoresistive behavior [5,6,9–11]. How- ever, strain effects alone are not responsible for all observed differences in the magnetic properties of nominally identical manganite films. Due to the substantial energy associated with the epitaxial strain, thicker films release the strain via the formation of misfit dislocations. But even though thick films show a bulk-like crystallographic *Corresponding author. IBM Almaden Research Center, 650 Harry Road, K63/E3, San Jose, CA 95120, USA. Fax: +1-408- 927-3008. E-mail address: aberger@us.ibm.com (A. Berger). 1 Permanent address: Departamento de F! ısica, Universidad del Valle, Cali, A.A. 25360, Colombia. 0304-8853/01/$ - see front matter r 2001 Elsevier Science B.V. All rights reserved. PII:S0304-8853(01)00482-6