  We report on high-field magnetic properties of the silver vanadium phosphate
Ag(2)VOP(2)O(7). This compound has a layered crystal structure, but the
specific topology of the V-P-O framework gives rise to a one-dimensional spin
system, a frustrated alternating chain. Low-field magnetization measurements
and band structure calculations show that Ag(2)VOP(2)O(7) is close to the dimer
limit with the largest nearest-neighbor interaction of about 30 K. High-field
magnetization data reveal the critical fields \mu_0H_{c1} of about 23 T
(closing of the spin gap) and \mu_0H_{c2} of about 30 T (saturation by full
alignment of the magnetic moments). From H_{c1} to H_{c2} the magnetization
increases sharply similar to the system of isolated dimers. Thus, the magnetic
frustration in Ag(2)VOP(2)O(7) bears little influence on the high-field
properties of this compound.
