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Submillimeter-wave ESR measurements of low-dimensional quantum spin systems.

Authors :: Ohta, H.
Okubo, S.
Kimura, S.
Sakurai, T.
Takeda, S.
Tanaka, T.
Kikuchi, H.
Nagasawa, H.
Source :: Applied Magnetic Resonance; Apr2000, Vol. 18 Issue 4, p469-474, 6p
Publication Year :: 2000
Abstract: Temperature-dependent electron spin resonance (ESR) measurements of two low-dimensional quantum spin systems, the S = 1/2 spin-ladder system Cu<subscript>2</subscript>(1,4-diazacycloheptane)<subscript>2</subscript>Cl<subscript>4</subscript> (Cu<subscript>2</subscript>(C<subscript>5</subscript>H<subscript>12</subscript>N<subscript>2</subscript>)<subscript>2</subscript>Cl<subscript>4</subscript>) and the gapless S = 1 bond-alternating one-dimensional antiferromagnet trans-Ni(333-tet)(N<subscript>3</subscript>)(ClO<subscript>4</subscript>), have been performed. X-band electron spin resonance (ESR) measurements of single-crystal Cu<subscript>2</subscript>(C<subscript>5</subscript>H<subscript>12</subscript>N<subscript>2</subscript>)<subscript>2</subscript>Cl<subscript>4</subscript> show the increase of linewidth and anisotropic g-shifts below 8 K similar to those known for one-dimensional antiferromagnet. On the other hand, Ni(333-tet)(N<subscript>3</subscript>)(ClO<subscript>4</subscript>) has broad line-width and ESR has been observed for the first time by our high-field ESR. Its linewidth increases as the temperature is decreased, while the g-shift seems to be isotropic and the g-value decreases as the temperature is decreased. This g-shift can be connected to the quantum fluctuation of the system. [ABSTRACT FROM AUTHOR]