Ferromagnetic CaRuO3

Abstract

The non-magnetic and non-Fermi-liquid CaRuO3 is the iso-structural analog of the ferromagnetic (FM) and Fermi-liquid SrRuO3. We show that an FM order in the orthorhombic CaRuO3 can be established by the means of tensile epitaxial strain. The structural and magnetic property correlations in the CaRuO3 films formed on SrTiO3 (100) substrate establish a scaling relation between the FM moment and the tensile strain. The strain dependent crossover from non-magnetic to FM CaRuO3 was observed to be associated with switching of non-Fermi liquid to Fermi-liquid behavior. The intrinsic nature of this strain-induced FM order manifests in the Hall resistivity too; the anomalous Hall component realizes in FM tensile-strained CaRuO3 films on SrTiO3 (100) whereas the non-magnetic compressive-strained films on LaAlO3 (100) exhibit only the ordinary Hall effect. These observations of an elusive FM order are consistent with the theoretical predictions of scaling of the tensile epitaxial strain and the magnetic order in tensile CaRuO3. We further establish that the tensile strain is more efficient than the chemical route to induce FM order in CaRuO3.

Co-appearance of superconductivity and ferromagnetism in a Ca2RuO4 nanofilm crystal

“…The impurity phase CaRuO 3 is a paramagnetic metal down to low temperature in bulk 37 . Although the behaviour of a ferromagnetic metal in CaRuO 3 films has been reported 38 , they are different from the electric and magnetic properties of our samples. CaRuO 3 films exhibit no diamagnetism 38 .…”

Electronic correlations, magnetism, and Hund's rule coupling in the ruthenium perovskitesSrRuO3andCaRuO3

“…Films show a different pattern of rotation and tilt than do bulk materials, and in films the rotation angles may be manipulated by strain. Calculations of the strain dependence of the mass enhancement and magnetic moment in thin films of SrRuO 3 and CaRuO 3 will be very interesting to perform and compare to experiment [46,97] and to previous LSDA results [44,45]. Studying theoretically the ruthenates within a wide energy window to include oxygen p and e g bands, which are both close to the frontier t 2g bands, is an interesting subject, too.…”

Quasilocal critical nature of cooperative paramagnetic fluctuations inCaRuO3metal

“…[1][2][3] In addition to the fundamental understanding, ruthenates perovskite of the form ARuO 3 , where A = Sr or Ca, have possible implications in the technologically important spintronics devices, especially in the thin film form where magnetic properties can easily be manipulated for desired applications as the spin-polarized tunnel junctions. [4,5] While SrRuO 3 is ferromagnetic (T c 160 K), the magnetic nature of CaRuO 3 is still a subject of debate. [5][6][7][8][9][10][11][12][13] Both compounds, however, exhibit interesting non-Fermi liquid (NFL) behavior at low temperature (T ≤40 K).…”

“…[4,5] While SrRuO 3 is ferromagnetic (T c 160 K), the magnetic nature of CaRuO 3 is still a subject of debate. [5][6][7][8][9][10][11][12][13] Both compounds, however, exhibit interesting non-Fermi liquid (NFL) behavior at low temperature (T ≤40 K). [11,[14][15][16] CaRuO 3 , in fact, undergoes a cross-over transition at T 30 K, which separates two NFL states with distinct power law exponents of electrical resistivity.…”