TY - JOUR
T1 - Ten layered hexagonal perovskite Sr5Ru5-xO 15 (x = 0.90), a weak ferromagnet with a giant coercive field H c ∼ 12 T
AU - Yamamoto, Ayako
AU - Hashizume, Daisuke
AU - Katori, Hiroko Aruga
AU - Sasaki, Takahiko
AU - Ohmichi, Eiji
AU - Nishizaki, Terukazu
AU - Kobayashi, Norio
AU - Takagi, Hidenori
PY - 2010/10/26
Y1 - 2010/10/26
N2 - A single crystal of Sr5Ru5-xO15 (x = 0.90(2)) with mixed valence of Ru(IV) and Ru(V) was synthesized under a high pressure of 4 GPa with an oxidizer. Sr5Ru5-xO15 crystallizes in a hexagonal perovskite-type structure with a space group P63/mmc (No.194), a = 5.5600(11) Å, and c = 22.830(5) Å. An alternative stacking of four corner-sharing (c) SrO3 layers and one face-sharing (h) SrO3 layer linking RuO6 octahedra and its doubling along c-axis gives a 10 layer period hexagonal cell (10H) which is denoted by (cccch)2. The partial deficiency of Ru found in face-sharing octahedra, as reported for 8H-Sr4Ru4-xO 12 (x = 0.95) with (ccch)2 stacking, yields an average Ru valence estimate of 4.87. The bond valence analysis indicates that the valence of Ru in fully corner-sharing octahedra is nearly 5, while that of Ru in face-sharing octahedra is considerably lower than 5. This compound is a weakly ferromagnetic metal with Curie temperature Tc = 160 K and a saturated moment of 0.07 and 0.05 μB/Ru in H ⊥ c and H // c, respectively. In the ferromagnetic state, we found remarkable enhancement of the coercivity below 50 K. At 1.7 K, a giant coercive field of ∼12 T was observed. We argue that Ru(IV,V) in face-sharing layers are responsible for the ferromagnetism and that possible glassy character due to frustration and disorder may at least in part contribute to the giant coercivity.
AB - A single crystal of Sr5Ru5-xO15 (x = 0.90(2)) with mixed valence of Ru(IV) and Ru(V) was synthesized under a high pressure of 4 GPa with an oxidizer. Sr5Ru5-xO15 crystallizes in a hexagonal perovskite-type structure with a space group P63/mmc (No.194), a = 5.5600(11) Å, and c = 22.830(5) Å. An alternative stacking of four corner-sharing (c) SrO3 layers and one face-sharing (h) SrO3 layer linking RuO6 octahedra and its doubling along c-axis gives a 10 layer period hexagonal cell (10H) which is denoted by (cccch)2. The partial deficiency of Ru found in face-sharing octahedra, as reported for 8H-Sr4Ru4-xO 12 (x = 0.95) with (ccch)2 stacking, yields an average Ru valence estimate of 4.87. The bond valence analysis indicates that the valence of Ru in fully corner-sharing octahedra is nearly 5, while that of Ru in face-sharing octahedra is considerably lower than 5. This compound is a weakly ferromagnetic metal with Curie temperature Tc = 160 K and a saturated moment of 0.07 and 0.05 μB/Ru in H ⊥ c and H // c, respectively. In the ferromagnetic state, we found remarkable enhancement of the coercivity below 50 K. At 1.7 K, a giant coercive field of ∼12 T was observed. We argue that Ru(IV,V) in face-sharing layers are responsible for the ferromagnetism and that possible glassy character due to frustration and disorder may at least in part contribute to the giant coercivity.
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U2 - 10.1021/cm1017954
DO - 10.1021/cm1017954
M3 - Article
AN - SCOPUS:77958110638
SN - 0897-4756
VL - 22
SP - 5712
EP - 5717
JO - Chemistry of Materials
JF - Chemistry of Materials
IS - 20
ER -