The paper deals with attenuation of transversal vibrations of a clamped-clamped beam loaded by a rigid mass at beam mid-point and excited by vertical force acting at beam mid-point. The novelty of treated approach is the use of a ferromagnetic conductor as the principal damping device. This is a different approach from that one used in contemporary research papers. Beyond vibration attenuation a concurrent shift in damped natural frequency due to the negative stiffness is observable. The theoretical results are complemented by measurements on a test stand. Up to 10 dB attenuation of the most marked resonance peak and frequency shift by up to 5 % to lower frequency was observed.