## 1 Introduction  
The electrocaloric (EC) effect has attracted great attention due to its potential to replace current domestic and industrial refrigeration systems to those based on solid-state cooling technology [1; 2; 3; 4; 5; 6; 7; 8; 9]. Usually, large EC effects in ceramics are reported within a narrow temperature range, sometimes even at a fixed temperature around the temperature of the ferroelectric (FE)-paraelectric (PE) phase transition above room temperature, which limits its applications. A wide operational temperature range near room temperature is highly desired in order to develop high performance EC cooling devices [10; 11; 12; 13; 14; 15; 16; 17; 18]. For instance, Sn\({}^{4+}\) doping was reported to increase the operating temperature range of the EC effect in Ba\({}_{0.9}\)Sr\({}_{0.1}\)(Ti\({}_{0.9}\)Zr\({}_{0.1}\))\({}_{0.95}\)Sn\({}_{0.05}\)O\({}_{3}\) ceramics to 20 K [13]. The modified Ba(Zr\({}_{x}\)Ti\({}_{1-x}\))O\({}_{3}\) ceramic generated a wide EC temperature change range at about 30 K [16] and 50 K in Y-substituted BaTiO\({}_{3}\) ceramics [19]; even a temperature span from room temperature to 140 \({}^{\circ}\)C (\(\sim\)115 \({}^{\circ}\)C range) in BaTiO\({}_{3}\) ceramics by rare-earth substitution was obtained [14]. According the results reported earlier, doping can vary the temperature range of different materials. Additionally, it has been demonstrated that the compressive or tensile strain induced by external stimuli (electric field, stress, pressure) can also remarkably change the spontaneous polarization of ferroelectrics, which influences the transition temperature range of the EC effect further [20; 21; 22; 23].  
Previous studies, in order to acquire a large adiabatic temperature change, mainly focused on the transition from the FE phase to the PE phase [24; 25; 26; 27]. Later, the EC effect of the electric field-inducedantiferroelectric (AFE) phase was proposed [15; 28; 29]. [PERSON] et al. [30] reported that the phase transition from the AFE to the FE phase led to a giant EC effect in PbZrO\({}_{3}\) thin films. [PERSON] et al. [31] reported a large positive EC effect in a broad temperature range (\(\sim\)110 K) in Pb\({}_{0.97}\)La\({}_{0.02}\)(Zr\({}_{0.65}\)Sn\({}_{0.3}\)Ti\({}_{0.05}\))O\({}_{3}\) (PLZST) relaxor AFE thin films. [PERSON] et al. [11] reported the coexistence of giant negative and positive EC effects in Na\({}_{0.5}\)Bi\({}_{4.5}\)Ti\({}_{4}\)O\({}_{15}\) (NBT) ferroelectric films over a broad temperature range. Surprisingly, the EC effect in NBT-based samples is caused by the FEAFE phase transition, which is different from previous FEPE and AEFEF phase transitions. The existence of the FEAFE phase transition in Sm-doping BiFeO\({}_{3}\) (BFO) systems have been reported [32; 33; 34], however, the EC effect of the phase transition from FE to AFE in Sm-doping BFO ceramics has never been explored. BFO has a high leakage of current due to the existence of oxygen vacancies or defects, while a reduction in leakage current was observed with increases in Sm composition [35; 36]. The breakdown of the electric field can be increased in Sm-doping BFO, hence the high entropy change also can be enhanced by chemical element doping. In this work, the existence of a giant electrocaloric response over a broad temperature range in the Sm-doping BFO system was investigated. The entropy change of different Sm-doping composition and hydrostatic pressure was calculated and discussed.