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We demonstrate that short-wavelength exchange-coupled magnons can be identified electrically through the combination of their spin-pumping and damping properties in a metal/magnetic insulator heterostructure. We present clear wave-vector dependence of the spin pumping from parametrically excited exchange-coupled magnons in the heterostructure. The efficiency of spin pumping by dipole-exchange magnons was measured to be sensitive to their wave numbers and propagation angles, while the efficiency was found to be almost constant in the exchange limit. This dependence enabled us to uncover nontrivial dual bistability in the system originating from drastic change in dominant nonequilibrium magnon modes. These findings pave a path for direct electric access to short-wavelength spin dynamics that cannot be probed by optical techniques.

Quantum phase modulation is achieved in a metallic nanoring with a $\mathrm{FeNi}∕\mathrm{Cu}∕\mathrm{FeNi}$ (ferromagnet/normal-metal/ferromagnet) layer. Both frequency and amplitude of Aharonov-Bohm oscillation are found to be modified with respect to the magnetization configurations, indicating that the phase modulation originates from the spin-orbit scattering induced by the magnetization of the ferromagnets. Such phase modulation is ``crossover'' phenomena between mesoscopic magnetism and microscopic quantum interference effects, which provides fundamental knowledge upon quantum spin transport.