The magnetic properties of the parent sample (x = 0.00)  undergoes a FM -PM transition at TC = 265 K. As the Ti4+ content increases, the magnetic transition shows a gradual trend towards broadening and shifting to a lower temperature, TC has been found 175 K and 114 K for x = 0.05 and 0.10, respectively. Since the Ti4+ ion is not magnetic, the substitution of Mn4+ by Ti4+ causes a decrease in the interactions of the double exchange (DE) ferromagnetic between Mn3+ and Mn4+ ions and in turn the transition temperature decreases .
To better understand the magnetic behavior, we have investigated the inverse of magnetic susceptibility χ-1(T) = ((µ0H/M)-1) as function of temperature at µ0H = 0.05 T for all our samples. In the paramagnetic phase (T > TC), this curve can be fitted by the Curie Weiss Low: χ= C/(T-Θ_p ) (4) Where C and Θ_p are the Curie constant and the Curie – Weiss temperature, respectively. χ-1(T) is shown in Fig .4. Fits with the Curie Weis Low equation using original program yield values of C and〖 Θ〗_p, the obtained values are given in Table 2. The positive value of Θ_p is assigned to the existence of ferromagnetic interactions between spins near TC. It is also noticed that the obtained values are higher than the transition temperatures with dT=Θ_p-T_C = 19 K and 18 K for x = 0.05 and x = 0.10, respectively. Generally, this difference depends on the substance and may be attributed to the presence of a magnetic inhomogeneity .
On the other hand, we have also determined the effective paramagnetic moment μ_eff^exp using the relation : (μ_eff^exp )^2=(3K_B)/(Nμ_B^2 ) C (5) where N, µB and kB are the Avogadro number, Bohr magneton and Boltzmann constant, respectively. According to La_0.65^(3+) Dy_0.05^(3+) Sr_0.3^(2+) Mn_0.65^(3+) Mn_(0.3-x)^(4+) Ti_x^(4+) O_3 compositions, the theoretical effective paramagnetic moment should be : 〖 μ〗_eff^th=√(0.05〖〖(μ〗_eff (Dy^(3+) ))〗^2+0.65〖〖(μ〗_eff (Mn^(3+) ))〗^2+(0.3〖〖-x)(μ〗_eff (Mn^(4+) ))〗^2 ) (6) With µeff (Mn3+) = 4.91µB,
Comparing the experimental values 〖(μ〗_eff^exp) to calculated ones (μ_eff^th), we have detected that the experimental effective paramagnetic moments are signiﬁcantly larger than the calculated ones. This difference can be related to the existence of ferromagnetic polarons in the paramagnetic state . 3.3. Magnetocaloric effect The temperature and ﬁeld dependence of the magnetization M (T, µ0H) was measured for all materials. Fig .5 shows isothermal magnetization curves for the La0.65Dy0.05Sr0.3Mn1-xTixO3 (x = 0.05 and 0.10) samples, measured at different magnetic applied ﬁelds between 0 and 5 T. Below TC, the M-µ0H data reveal similar ferromagnetic behavior and the magnetization increases sharply with the ﬁeld for µ0H < 0.5 T.
To determine the nature of the magnetic phase transition (first or second order), we have deduced the Arrott plots (µ0H/M vs.M2) from M (µ0H) plots , these curves are shown in Fig. 6. We can notice that, these plots display positive slopes, which indicates a characteristic of the second-order magnetic phase transition for our samples, according to Banerjee’s criterion . In contrast, a negative slope corresponds to a ﬁrst-order magnetic transition. Interestingly, the magnetocaloric effect (MCE) is an intrinsic property of magnetic materials. It is the response of the material toward the application or removal of a magnetic ﬁeld. This response is maximized when the material is near its magnetic transition temperature.
Using the isothermal magnetization data and based on Maxwell\’s relation, ΔSM can be calculated by the following equation : 〖ΔS〗_M (T,μ_0 H)= ∑_i▒(M_(i+1)-M_i)/(T_(i+1)-T_i ) 〖Δμ_0 H〗_i (7) Were M_i and M_(i+1) are the magnetization values measured under a magnetic field µ0H at T_i and T_(i+1) , respectively. Fig .7(a and b) shows the thermal variation of the magnetic entropy, (-〖ΔS〗_M) as function of temperature with a ﬁeld change of 1-5 T for the La0.65Dy0.05Sr0.3Mn1-xTixO3 (x = 0.05 and 0.10) samples. As seen from Fig .7 (a and b), the peak of 〖-ΔS〗_M^max increases with increasing the value of applied magnetic ﬁeld for each compositions but the peak position is nearly unaffected because of the second order nature of the magnetic phase transition  in these samples. The maximum values of magnetic entropy change (〖⃓ΔS〗_M^max⃓) observed for x = 0.05 and x = 0.10 are found to be 1.79 J/kgK and 1.49 J/kgK respectively at µ0H = 5 T. While, it was found to be 2.19 J/kgK for the parent sample (x = 0.00) .
Thereby, introducing Ti into Mn-sites is not favorable to enhance 〖-ΔS〗_M^max due to the weakening of the ferromagnetic state. These values are smaller than that of pure Gadolinium (Gd) metal whose 〖⃓ΔS〗_M^max⃓ is about 9.4 J/kgK  at µ0H = 5 T. However, the perovskite manganites are at relatively low cost when compared to the Gd and with other advantages such as their simple and inexpensive fabrication technologies and ease in tuning the working temperature range.