We report novel effects of randomness in the S=1 bond-alternating
antiferromagnetic chain compound with a dimer-singlet ground state
[Ni(N,N'-bis(3-aminopropyl)propane-1,3-diamine(mu-NO2]ClO4 abbreviated as
NTENP. The 15N NMR spectra develop a continuum with sharply peaked edges at low
temperatures, indicating an inhomogeneous staggered magnetization induced by
magnetic field. We attribute this to random anisotropic interactions due to
disorder of NO2 groups in the chains. The field-induced antiferromagnetic
transition exhibits remarkably anisotropic behavior. We propose that a
field-induced incoherent magnetization is transformed into a coherent
antiferromagnetic moment with spatially fluctuating amplitude.Comment: 4pages, 5 figues, submitted to J. Phys. Soc. Jp