Check this link

https://www.forbes.com/sites/bernardmarr/2016/12/08/what-is-the-difference-between-deep-learning-machine-learning-and-ai/

Shortly: Machine learning is the field of computer science that studies algorithms that can learn from and make decision on data. In other words, machine learning gives you the possibility to improve the performance P of a task T (your goal), by learn from experience E (your data).

Deep learning is a strategy/approach to implement machine learning.

I recommend you Goodfellow-Bengio-Courville's book to deeply study this subject: http://www.deeplearningbook.org/

see this link :

https://blogs.nvidia.com/blog/2016/07/29/whats-difference-artificial-intelligence-machine-learning-deep-learning-ai/

Machine learning is a branch of computing that gives computers the ability to learn from experience captured in data. Several learning algorithms exist and they include decision tree, Naive Bayes, Support Vector Machine(SVM), Logistic Regression, Linear Regression and most importantly(based on the context of your question), the Neural Networks and so on. 

Deep Learning Networks are actually Neural Networks that have multiple hidden layers which give it the ability to glean complex non-trivial pattern from data. It has led to major breakthroughs in Artificial Intelligence research recently.

Thanks to All for your answers.  Mr. Chinedu Pascal according to you, that deep learning extract non-trivial patterns but machine learning and data mining algorithms are also practiced for this purpose. Can you please me tell for which purpose Deep Learning is used. Can we used deep learning instead of ML.