Reduced ferromagnetic transition temperatures inSrRu1−vO3perovskites from Ru-site vacancies

Abstract

We show that annealing of stoichiometric SrRuO 3 perovskites in high-pressure oxygen of 600 atm near 1100°C produces SrRu 1−v O 3 compounds with vacancies on the Ru-sites. The creation of Ru vacancies rapidly suppresses the ferromagnetic ordering temperature, T C , from 163 K to 45 K with an increase of v Ϸ 0.09. Subtle structural changes that accompany the creation of Ru-site vacancies are different from the typical properties of transition metal perovskites, for which an increased formal oxidation state of the B-site cations normally leads to decreased B-O interatomic distances and contraction of the unit cell volume. The reduced charge screening caused by the Ru-vacancies offsets an expected decrease of the average interatomic distance Ru-O and rotation of the RuO 6 octahedra as Sr atoms relax toward Ru-vacancies increases the observed volume.

Functional links between stability and reactivity of strontium ruthenate single crystals during oxygen evolution

“…Based on the above results and discussion, we propose that both Sr and Ru are more stable for the highly ordered (morphological effect) and low-energy (electronic effect) SRO(001) surfaces than for the more defective, high-energy surfaces with the (110) and (111) orientations. The degradation of the SRO films may be controlled by a combination of the electrochemical dissolution of Ru and the chemical corrosion of Sr 62 . Although the physical origin and behavioural details of the degradation of SRO(hkl) are difficult to assess (studies along these lines are highly hypothetical even for 'simple' monometallic oxides such as Pt and/or Ru oxides), in the following, we explore the manner and extent to which the applied potential may influence the dissolution of Sr and Ru.…”

Pulsed laser deposition of SrRuO3 thin-films: The role of the pulse repetition rate

“…Again, this observation is in accordance with the assumption of a decrease in Ru content with increasing repetition rate of the different films. 12,21,[29][30][31][32][33] In brief, we can conclude that despite the drawbacks of the individual methods, measurements of the surface composition, structural and electrical properties of as-deposited SrRuO 3 thin films build a coherent picture that the increase in the laser repetition rate results in a decrease in Ru content in these films.…”

“…This might be due to the preparation conditions of the target itself, as the loss of volatile RuO x is a known issue in this context as well. 21 Another potential reason for the observed difference from ideal behaviour is that the information depth of XPS is limited to first few nm's of the sample. As our target was constantly exposed to low-pressure conditions in the PLD chamber, its surface and the bulk composition might slightly deviate from each other.…”

“…The same trend of ruthenium non-stoichiometry with out-of-plane lattice parameters was observed in numerous previous studies. 12,21,25 Temperature dependent measurements of the electric resistivity in the range of 2 ≤ T /K ≤ 300 were performed and the data are shown in Fig. 3.…”

Influence of Hydrostatic Pressure on Magnetic Properties of (Sr,La)(Ru,Cr,Mn)O3

“…The stoichiometric SrRuO 3 , La 0.2 Sr 0.8 RuO 3 , and the SrRu 0.9 M 0.1 O 3 (M = Mn and Cr) samples have been prepared using standard ceramic synthesis method [13]. All the magnetic measurements were performed in the temperature range of 5-250 K at magnetic field up to 16 kOe using a PAR 4500 vibrating sample magnetometer.…”