Before revision: In this paper, we create a model of unexpected fluctuation of the long-term real interest rate. This model is based on our new version of IS-LM model. The new IS-LM model eliminates two main deficiencies of the original model: assumptions of constant price level and of strictly exogenous money supply. The unexpected fluctuations of the long-term real interest rate can be explained by existence of special type of cycle called relaxation oscillation on money (or financial assets) market.
After revision: In this paper, we present own point of view how the unexpected fluctuations of the long-term real interest rate can be explained by existence of special type of cycle called relaxation oscillation on money (or financial assets) market.