  Detailed magnetic studies including magneto-caloric measurements on magnetic
multiferroic quadruple perovskite CaMn7O12 are presented. Based on the
collective response of Arrott plots and {\Delta}SM (T), a magnetic phase
diagram of CaMn7O12 is suggested. A new magnetic transition at TN3 ~20 K where
the system changes from noncollinear AFM to collinear AFM is reported. An
anomaly observed in both {\Delta}SM (T) and Arrott plots around 64 K has been
attributed to high external field induced spin canting leading to change in
magnetic order inducing phase transition. Magneto-caloric effect in this
material is presented for the first time. The peak value of change in
isothermal magnetic entropy is 1.3 J/K-Kg and the value of refrigeration
capacity is reported to be 34.5 J/Kg for the field of 7 T.
