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We report on in situ heat capacity measurements (370–800 K) using quasiadiabatic ultrafast differential scanning nanocalorimetry in thin films (1–200 nm) of Ni grown by electron beam evaporation. The heat capacity shows a broad peak with a rounded maximum that is attributed to the decrease of long-range interactions in the ferromagnetic to paramagnetic phase transition of Ni. The calorimetric data exhibit a reduction of the Curie temperature as the thickness of the films (or the average grain size) decreases. The magnitude of the jump in specific heat at TC scales with the number of surface or interface atoms. [ABSTRACT FROM AUTHOR]

Ultrastable thin film glasses transforminto supercooled liquidvia propagating fronts starting from the surface and/or interfaces.In this paper, we analyze the consequences of this mechanism in theinterpretation of specific heat curves of ultrastable glasses of indomethacinfor samples with varying thickness from 20 nm up to several microns.We demonstrate that ultrastable films above 20 nm have identical fictivetemperatures and that the apparent change of onset temperature inthe specific heat curves originates from the mechanism of transformationand the normalization procedure. An ad hoc surface normalization ofthe heat capacity yields curves which collapse into a single one irrespectiveof their thickness. Furthermore, we fit the surface-normalized specificheat curves with a heterogeneous transformation model to evaluatethe velocity of the growth front over a much wider temperature intervalthan previously reported. Our data expands previous values up to Tg+ 75 K, covering 12 orders of magnitude in relaxation times. The resultsare consistent with preceding experimental and theoretical studies.Interestingly, the mobility of the supercooled liquid in the regionbehind the transformation front remains constant throughout the thicknessof the layers. [ABSTRACT FROM AUTHOR]

Abstract: High quality stoichiometric EuO ferromagnetic thin films have been grown by Molecular Beam Epitaxy (MBE) on MgO coated-Yttria Stabilized Zirconia (YSZ) (100) substrates. The proof is made that introducing an MgO buffer layer, that avoid oxygen transfer from YSZ to EuO, allows the preparation of high quality stoichiometric EuO films at reduced deposition temperature compared with films directly deposited onto YSZ, maintaining similar Eu flux and oxygen partial pressure. Structure and texture were characterized by X-ray diffraction showing out-of plane and in-plane ordering for films deposited onto MgO buffer layers. The crystallographic quality was corroborated by a Curie temperature around 69K and a magnetization moment close or equal to 6.49·10−23 J/T (7 μB), corresponding to bulk EuO single crystal values. [Copyright &y& Elsevier]