Lunar Calendar and Ramadan Effect on Islamic Mutual Funds Performance in Pakistan

This report is principally intended to ascertain out the result of the lunar calendar with special focus on the holy month of Ramadan on the operation of Islamic mutual funds in Pakistan. Economic activity in Pakistan demands a different turn due to observation of fast and short working hours in the country in the month of Ramadan. This work utilizes the logit model to investigate the impact of lunar calendar generally and the holy month of Ramadan, specifically along the net asset values of the mutual fund. This study confirms lower expected growth of net asset value in the month of Ramadan and the other stages of the religious sentiment. Economic activity regains pace after Ramadan and Zulhajjah as evident from the probable increase of net asset value of the Islamic mutual funds in the month of Shawwal & Moharram following months of the Ramadan and Zulhajjah respectively.

Experimental & Theoretical Investigations of Fe and A1 Based Spinels

Spinel oxides are an important class of versatile materials, which exhibit complex and tunable structures and offer exceptional properties for their potential applications in wide range of modern fields. In this dissertation, two important classes of spinel materials based on iron and aluminum are reported to have been synthesized and characterized experimentally. These are also checked theoretically for their possible applications in electronic and spintronic devices.Firstly, iron based spinel i.e., MgFe2O4, NiFe2O4, and CrFe2O4 were synthesized by sol-gel method whilst thin films were deposited on copper substrates by spin coating technique. In case of MgFe2O4, Mg/Fe ratio was varied as 0.4, 0.45, 0.5, 0.55 and 0.6 during sol synthesis. Variation of Mg/Fe ratio strongly affected magnetic and electronic properties along with phase purity of magnesium iron oxide thin films. Peaks corresponding to (220), (222), (400), (331), and (620) planes confirmed formation of MgFe2O4 at a very low annealing temperature of 300 oC with Mg/Fe ratio of 0.55. A single magnetic phase has been achieved with high dielectric constant and low tangent loss at Mg/Fe ratio of 0.55. Semiconducting behavior, revealed by Arrhenius plot, is due to electron hoping between Fe2+ and Fe3+ cations. High saturation magnetization of 163emu/cm3 is achieved which decreased at Mg/Fe values of 0.4, 0.45, 0.5 and 0.6. For NiFe2O4, nickel oxide (NiO) was added to hematite (Fe2O3) and NiFe2O4 phase formation was achieved at 6% Ni dopant concentration. Variation of Ni dopant was observed to strongly affect structural, magnetic and dielectric properties. Particle size of around 10 nm was observed through SEM. High saturation magnetization of 25 emu/g, and dielectric constant of 94 was observed with 6% of Ni dopant concentration. High dielectric constant and low dielectric loss of NiFe2O4 was observed at high frequency that is very interesting for high speed electronic and spintronic devices. Furthermore, antiferromagnetic Cr3+ was added in NiFe2O4 by co-precipitation method. This enhances the utility in magnetic storage, computer memory chips and microwave devices. Single-phase cubic spinel structure was achieved with particle size in the range of 38-49 nm. Structural study revealed phase purity of CrFe2O4 spinel at dopant concentration of 6wt% and again at 9-10wt% with crystal size of 15.45 nm and 14.98 nm respectively. Mixed phases of Fe2O3, Cr5O12, CrFe2O4 or amorphous nature was observed for rest of the dopant concentration ranges. vii Secondly, aluminum based spinel, i.e., FeAl2O4 and ZnAl2O4 were synthesized by sol-gel technique and then the sol was spun on copper substrates with variation in Fe/Al ratio as 0.4, 0.45, 0.5, 0.55 and 0.6. XRD patterns revealed that phase pure FelAl2O4 was observed only for the sample with Fe/Al ratio of 0.4. Whereas, Fe2O3 peaks appeared along with iron aluminum oxide peaks for rest of the ratios. M-H curves showed enhanced magnetic properties of films having 42.325 emu/cm3 saturation magnetization, 10 emu/cm3 remnant magnetization, and 430.19 Oe coercivity. Conductivity measurements showed transition in electrical properties at a temperature of 127 K. Room temperature magnetoresistance ̴ 10% was observed for iron aluminum oxide thin films with Fe/Al of 0.4. For ZnAl2O4, glass substrate was used for preparation of thin films by spin coating. Dopant concentration (1-10%) was carried out beyond the solid solubility limit to allow further reaction of ZnO and dopant oxide for the formation of phase-pure ZnAl2O4. XRD results confirmed formation of phase pure ZnO in undoped films with preferred orientation along (101) plane. ZnO phase persisted with aluminum doping till 3% along with change in preferred orientation from (101) to (001) plane. Mixed ZnO, Al2O3, ZnAl2O4 phases were observed at dopant concentrations of 4-6% and 9-10%. Phase pure ZnAl2O4 was obtained at dopant concentrations of 7-8%. Films showed high transmission in the visible and infrared regions. Highest transmission ~ 91% with band gap of 3.756 eV was observed for ZnAl2O4 films with dopant concentration of 8%. Refractive index of 2.16 at 500nm was observed at this dopant concentration whereas dielectric constant of 64.86 (log f=5.0) was observed due to high grain boundary resistance of 3.218 MΩ as determined by ZView software. Temperature dependent dielectric analysis indicated negative temperature coefficient for ZnAl2O4 thin films with activation energy of 1.86 eV.Thirdly, ab-initio calculations were performed to calculate structural, electrical and magnetic properties for MgFe2O4, CrFe2O4, NiFe2O4, FeAl2O4 and ZnAl2O4 by using Density Functional Theory. Generalized Gradient Approximation (GGA) without and with U (PBE, PAW and modified Becke Johnson (mBJ) potentials) was implemented to accomplish theoretical investigations. Experimental results obtained so far are in good agreement with the theoretical observations.