The magnetic properties of a two-dimensional spin-gap compound SrCu2(BO3)(2
), realizing the Shastry-Sutherland model, were investigated using high-qua
lity single crystals. The analysis of the temperature-dependent magnetic su
sceptibility revealed a spin gap of 34K. The magnetization curve at 0.4K po
ssibly has, in addition to the already established one-quarter and one-eigh
th plateaux, another quantized plateau at one-tenth of the full Cu moment,
which is one of the plateaux predicted by Miyahara and Ueda.