Spin-dependent transport in the double-perovskite Sr2CrWO6

Abstract

We report on the preparation and characterization of the double-perovskite compound Sr2CrWO6 with a Curie temperature of 390 K. We have fabricated both Sr2CrWO6 bulk sintered polycrystalline bars and high-quality epitaxial thin films on SrTiO3 substrates by pulsed-laser deposition. The samples were characterized by thermogravimetric analysis, x-ray diffraction, electrical transport, and magnetization measurements. Polycrystalline samples containing a large number of grain boundaries show a large low-field magnetoresistance of up to 100% at 5 K. At room temperature, this effect is reduced to a few percent. Our results show that Sr2CrWO6 is an interesting candidate for room-temperature magnetoelectronic materials.

Structural and doping effects in the half-metallic double perovskiteA2CrWO6(Philipp1, Majewski2, Alff3 et al. 2003Phys. Rev. BSelf Cite367161650View full textAdd to dashboardCite

“…Furthermore, in Sr 2 FeMoO 6 an increase in T C of about 70 K has been reported as a result of electron doping by partial substitution of divalent Sr 2+ by trivalent La 3+ [4]. With respect to magnetoresistance, up to now large lowfield magnetoresistive effects have been found not only in Sr 2 FeMoO 6 [1,5,6], but also in many other double perovskites as for example Sr 2 FeReO 6 [7], Sr 2 CrWO 6 [8], and (Ba 0.8 Sr 0.2 ) 2−x La x FeMoO 6 [9].…”

Epitaxial growth and transport properties of Sr2CrWO6 thin films

“…The saturation magnetization M S was found to strongly depend on the growth conditions and the substrate material. A maximum value of M S = 1.9 µ B /f.u at 5 K was obtained for a 48 nm thick film grown on (111) SrTiO 3 [7] or Argon atmosphere [5,8,16] in a temperature range between 700 and 900 • C. Under these conditions (e.g. T = 800 • C, p O 2 = 1 × 10 −8 Torr) the surface of the SrTiO 3 substrates becomes oxygen deficient within a few minutes.…”

“…T C = 635 K in Sr 2 CrReO 6 [2]. Large low field magnetoresistance effects are found in Sr 2 FeMoO 6 [1,3], Sr 2 FeReO 6 [4] and Sr 2 CrWO 6 [5]. Thin films of the well studied system Sr 2 FeMoO 6 have been fabricated by pulsed-laser deposition (PLD) at relatively high temperatures of about 900 • C [6].…”

“…Due to the good lattice match, epitaxial films of this material can be grown on SrTiO 3 substrates in a molecular layer-by-layer growth mode resulting in high crystalline quality. Sr 2 CrWO 6 thin films were deposited from stoichiometric targets [5] on atomically flat, HF etched and annealed (001) SrTiO 3 substrates by PLD using a 248 nm KrF excimer laser [9]. Fig.…”

“…Nevertheless, the measured Curie temperature is well above 400 K. Due to the reducing growth atmosphere required for double perovskites, the SrTiO 3 substrate surface undergoes an insulator-metal transition impeding the separation of thin film and substrate electric transport properties. [5]. Thin films of the well studied system Sr 2 FeMoO 6 have been fabricated by pulsed-laser deposition (PLD) at relatively high temperatures of about 900 • C [6].…”