In　this　work,　we　reported　a　large　electrocaloric　effect　(ECE)　in　tetragonal　perovskite　0.03　Bi(Mg1/2Ti1/2)O-3-0.97　(0.875Bi(1/2)Na(1/2)TiO(3)-0.125BaTiO(3))　ceramic.　It　was　found　that　the　composition　demonstrates　a　coexisting　state　of　the　ferroelectric　P4mm　and　relaxor　P4bm.　Due　to　the　field-induced　phase　transition　from　relaxor　with　P4bm　symmetry　to　ferroelectric　with　P4mm　symmetry,　a　positive　ECE　is　observed　in　the　temperature　range　of　25-130　degrees　C.　Under　an　electric　field　of　4　kV/mm,　a　large　temperature　change　Delta　T　of　0.75　degrees　C　was　achieved　at　80　degrees　C,　and　the　EC　responsivity　Delta　T-max/Delta　E　of　0.19　K.cm/kV,　indicating　a　promising　lead-free　material　for　potential　application　in　solid-state　refrigerators.　(C)　2018　Acta　Materialia　Inc.　Published　by　Elsevier　Ltd.　All　rights　reserved.