Crystallographically aligned ferroelectric films usable in memories and method of crystallographically aligning perovskite films

A method of forming a ferroelectric thin film, comprising the steps of:

• a first step of depositing a ferroelectric layer comprising a ferroelectric material upon a singly crystalline body held at a deposition temperature at which said ferroelectric material is stable in a cubic phase;
• and
• cooling said deposited layer through a transition temperature of said ferroelectric material lower than said deposition temperature and producing a transition in said ferroelectric material from said cubic phase to a non-cubic phase, said cooling being performed at a cooling rate lying within a range between 10.degree. to 40.degree. C./min.

A method of writing and rejuvenating a ferroelectric memory, comprising:

• a first step of applying a voltage pulse of a first magnitude and a first duration to a ferroelectric memory comprising a singly crystalline ferroelectric material and a pair of electrodes to thereby write a datum in said memory;
• and
• a second step of applying a voltage pulse of a magnitude approximately equal to said first magnitude and of a second duration very much larger than said first duration to said ferroelectric memory to thereby rejuvenate said memory for said first step.

A method of growing an oriented perovskite thin film, comprising the steps of:

• depositing a perovskite thin film upon a crystalline substrate;
• during said depositing step gradually changing deposition conditions from first growth conditions favoring formation of an a,b-axis oriented film to second growth conditions favoring formation of a c-axis oriented film, thereby forming a first portion of said thin film;
• after completion of said changing step, without interruption continuing said depositing step at said second growth conditions to form a second portion of said thin film, whereby said second portion is formed as an a,b-axis oriented thin film.