Borderline magnetism inSr4Ru3O10: Impact of La and Ca doping on itinerant ferromagnetism and metamagnetism

Abstract

-dependence of the resisitivity. The drastic changes caused by the dilute doping demonstrate a rare borderline magnetism that is delicately linked to the interplay of the density of states and spin-orbit coupling.

Anomalous itinerant magnetism in single-crystalSr4Ru3O10: A thermodynamic and transport investigation

“…The jump in C/T is drastic and persists up to ~12 K, suggesting a critical end point of the metamagnetic transition (Fig.3b). Relevantly, Ladoping pushes the anomalies to lower T and B, indicating that a QCP is reached near 13% of La-doping [11]. As shown in Fig.3c This is consistent with the behavior of C which at low T starts to decrease when B>5 T.…”

“…This is an indication that in the range 0.13 < x < 0.15 of La-doping a QCP is reached [11]. Cadoping, on the other hand, introduces only minor changes, so that chemical pressure does not appear to be a tuning parameter for the QCP [11]. The effects of a QCP are often farreaching and the results discovered in this paper [e.g., ΔC/T ~ -ln(T) and power laws in the resistivity] are believed to be in part due to the quantum critical fluctuations.…”

“…In this paper, we report the temperature and field dependence of the specific heat, resistivity and magnetization of triple-layered Sr 4 Ru 3 O 10 . Critically driven by both, intralayer fieldinduced metamagnetism and interlayer spontaneous ferromagnetism [7][8][9][10][11][12], unusual power laws in T are found. These features are distinct from those observed in other systems involving a QCP.…”

“…unusual low temperature specific heat [9], strong spin-lattice coupling [10,11], switching behavior [12] and other properties [13,14]. The unique feature, however, is borderline magnetism: For a field along the c-axis (perpendicular to the layers), Sr 4 Ru 3 O 10 displays spontaneous ferromagnetism at a Curie temperature, while for a field within the ab-plane it features a pronounced peak in magnetization and a first-order metamagnetic transition [7][8][9][10][11]. The c-axis ferromagnetism indicates that the Stoner criterion is satisfied, Ug(E F )≥1, where U is an exchange interaction and g(E F ) the density of states at the Fermi surface.…”

Unusual heavy-mass nearly ferromagnetic state with a surprisingly large Wilson ratio in the double layered ruthenates(Sr1−xCax)Qu1, Spînu2, Yuan3 et al. 2008Phys. Rev. B294491View full textAdd to dashboardCite

“…14,15 However, there exists a remarkable difference between the reported Curie temperatures: T c Ϸ 3 K for the polycrystalline samples 14 and T c Ϸ 100 K for the single-crystalline samples. 15 This discrepancy may originate from an impurity phase since the RP series easily involves the intergrowth of members of different n. [16][17][18] In this Rapid Communication, we report results of mag-netization, specific heat, and Hall effect for ͑Sr 1−x Ca x ͒ 3 Ru 2 O 7 single-crystalline samples grown by the floating-zone technique. A magnetic phase diagram, which reveals unusual phenomena, has been obtained due to the improved sample quality.…”