Structural stability and electronic properties in Al2O3–Cr2O3 mixed crystal

Kitaoka, Yukie; Nakamura, Kohji; Akiyama, Toru; T, Ito

doi:10.1016/j.jcrysgro.2011.12.091

Cited by 10 publications

(2 citation statements)

References 19 publications

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“…Specifically, we demonstrate the growth of high-quality corundum Cr (2-x) Al (x) O 3 (0001) thin films in the concentration range between x = 0 to x = 0.6, successfully verifying the suitability of the hybrid growth procedure for Chromia-based alloy fabrication, which extends our previous work on high-quality pure α-Cr 2 O 3 thin film growth [12,13]. The samples show a linear variation of the lattice constants a and c with x, as well as a monotonic decrease of the Néel temperature with x similar to the results of studies on bulk polycrystalline alloy samples [19,20,21,22]. In contrast with those studies, the highly oriented epitaxial nature of our alloy film samples allows the use of the boundary magnetization as a probe to study the magnetic transition.…”

Section: Discussionsupporting

confidence: 85%

“…α-Al 2 O 3 in its single crystalline form sapphire has been demonstrated to allow for epitaxial growth of Chromia films due to the advantage of structural isomorphism and relatively low lattice mismatch, given that |∆ |/ = 4.0% and |∆ |/ = 4.6% [8,10,12,13,18]. Correspondingly, Cr (2-x) Al (x) O 3 alloy films with (0001) surface orientation are a most suitable test case for the investigation of structural and magnetic properties, especially in terms of the robustness of boundary magnetization, which has been entirely unexplored so far [19,20,21,22]. In this work, we present a detailed study of the structural and magnetic properties of epitaxial Cr (2-x) Al (x) O 3 alloys in the composition range of x = 0 -0.6 .…”

Section: Introductionmentioning

confidence: 99%

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Boundary magnetization properties of epitaxialCr2−xAlxO3thin fi

2015

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The magnetoelectric antiferromagnet α-Cr 2 O 3 (Chromia) is known to possess a roughness insensitive net equilibrium magnetization at the (0001) surface, called boundary magnetization (BM), which is coupled to the bulk antiferromagnetic order parameter. In order to verify whether this symmetry sensitive BM persists in alloys, we investigate the impact of diamagnetic dilution on Chromia thin films alloyed with the isostructural α-Al 2 O 3 (Alumina). Single crystalline Cr (2-x) Al (x) O 3 thin films with (0001) surface orientation and varying stoichiometry have been grown by sputter co-deposition in the concentration range between x = 0 and x = 0.6 . For these samples, we find the corundum crystal structure, the antiferromagnetic ordering and the boundary magnetization to be preserved. We also find that the critical temperature T N can be tuned by alloying with α-Al 2 O 3, using the BM as a probe to study the magnetic phase transition. Furthermore, we were able to evaluate the critical exponent and the absolute BM values for different samples. Both properties corroborate that the observed magnetic signals originate from the BM rather than the bulk of the samples.2

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