  Quantized spin excitations in a single ferromagnetic microstrip have been
measured using the microwave photovoltage technique. Several kinds of spin wave
modes due to different contributions of the dipole-dipole and the exchange
interactions are observed. Among them are a series of distinct dipole-exchange
spin wave modes, which allow us to determine precisely the subtle spin boundary
condition. A comprehensive picture for quantized spin excitations in a
ferromagnet with finite size is thereby established. The dispersions of the
quantized spin wave modes have two different branches separated by the
saturation magnetization.
